JP2006235386A - Hologram recording material and optical recording material using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hologram recording material which can attain all of high sensitivity, high diffraction efficiency, satisfactory storage property, a low shrinkage rate, dry processing, multiplex recording characteristic (high recording density) and which is applicable for a high density optical recording medium, a three-dimensional display, a holographic optical element and the like. <P>SOLUTION: The hologram recording material and the optical recording medium using the same have a light refractive index modulation component and a curable polymer, wherein the light refractive index modulation component is the component to record the interference fringes as refractive index modulation by a method of any among (1) a color development reaction, (2) a latent image color development-chromogen self-sensitization amplification color reaction, (3) a latent image color development-chromogen sensitization polymerization reaction, (4) an orientation change of a compound having an intrinsic refractive index, (5) a dye decoloration reaction, and (6) a residual decoloration dye latent image-latent image sensitization polymerization reaction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hologram recording material applicable to a high-density optical recording medium, a three-dimensional display, a holographic optical element, and the like, and an optical recording medium using the same.

  General principles relating to hologram production are described in chapter 2 of several literatures and technical books such as “Holographic Display” (Junpei Uchinai, Sangyo Tosho [Non-Patent Document 1]). According to these, the photosensitive hologram recording material is placed at a position where one of the two light fluxes of the coherent laser light is irradiated onto the recording object and the total reflection light from the recording object can be received. The hologram recording material is directly irradiated with the other coherent light in addition to the reflected light from the object without hitting the object. Reflected light from the object is referred to as object light, and light directly applied to the recording material is referred to as reference light, and interference fringes between the reference light and object light are recorded as image information. Next, when the processed recording material is irradiated with the same light (reproduction illumination light) as the reference light, it is diffracted by the hologram so as to reproduce the wavefront of the reflected light that first reaches the recording material from the object during recording. As a result, an object image substantially the same as the real image of the object can be observed three-dimensionally.

A hologram formed by causing the reference light and the object light to enter the hologram recording material from the same direction is called a transmission hologram. The interference fringes are formed at intervals of about 1000 to 3000 per 1 mm in a form perpendicular or nearly perpendicular to the recording material film surface direction.
On the other hand, holograms formed by being incident on opposite sides of the hologram recording material are generally called reflection holograms. The interference fringes are formed at intervals of about 3000 to 7000 per 1 mm in a shape parallel or nearly parallel to the recording material film surface direction.
The transmission hologram can be created by a known method as disclosed in, for example, Japanese Patent Laid-Open No. 6-43634 [Patent Document 1]. The reflection hologram can be created by a known method disclosed in, for example, JP-A-2-3082 [Patent Document 2] and JP-A-3-50588 [Patent Document 3].

On the other hand, a hologram whose film thickness is sufficiently thick with respect to the interference fringe interval (usually a thickness of about 5 times the interference fringe interval or about 1 μm or more) is called a volume hologram.
On the other hand, a hologram whose film thickness is about 5 times or less of the interference fringe interval or about 1 μm or less is called a planar type or a surface type.

  Further, a hologram that records interference fringes by absorption of a dye or silver is called an amplitude hologram, and a hologram that is recorded by surface relief or refractive index modulation is called a phase hologram. Amplitude holograms are not preferred in terms of light utilization efficiency because light diffraction efficiency or reflection efficiency is significantly reduced due to light absorption, and phase holograms are usually preferred.

In the volume phase hologram, the phase of light can be modulated without absorbing light by forming a large number of interference fringes having different refractive indexes in the hologram recording material instead of optical absorption.
In particular, reflective volume phase holograms, also called Lippmann holograms, are capable of full color, white reproduction and high resolution with high diffraction efficiency due to wavelength selective reflection by black diffraction, and high resolution full color 3D display. Can be provided.
Recently, taking advantage of the wavelength selective reflection, a hologram optical element represented by a head-up display (HUD) mounted on an automobile, a pickup lens for an optical disk, a head-mounted display, a color filter for liquid crystal, a reflective liquid crystal reflector, and the like. (HOE) has been widely put into practical use.
In addition, practical use or application to, for example, lenses, diffraction gratings, interference filters, optical fiber couplers, facsimile optical polarizers, architectural window glass, and the like are being studied.

By the way, in the recent trend of advanced information society, networks such as the Internet and high-definition TVs are rapidly spreading. HDTV (High Definition)
(Television) will soon be on the air, and there is an increasing demand for high-density recording media for recording 100 GB or more of image information inexpensively and easily for consumer use.
Furthermore, in the trend of increasing computer capacity, there is a need for ultra-high-density recording media that can record large volumes of information of about 1 TB or more at high speed and low cost for business use such as computer backup and broadcast backup. It has been.
Under such circumstances, a compact, inexpensive optical recording medium that is replaceable and randomly accessible has attracted more attention than a magnetic tape medium that cannot be randomly accessed and a hard disk that is not replaceable and easily failed. However, an existing two-dimensional optical recording medium such as a DVD-R has a sufficiently large recording capacity that can meet future demands, even if the recording / reproducing wavelength is shortened, even if the recording / reproducing wavelength is shortened, at most about 25 GB on one side. This is a situation that cannot be expected.

  Therefore, a three-dimensional optical recording medium that performs recording in the film thickness direction has attracted attention as the ultimate ultra-high density recording medium. As a promising method, there are a method using a two-photon absorption material and a method using holography (interference). Therefore, a volume phase hologram recording material has recently attracted attention as a three-dimensional optical recording medium (holographic memory). It became so.

  In a holographic memory using a volume phase hologram recording material, two-dimensional digital information (referred to as signal light) using a spatial light modulation element (SLM) such as DMD or LCD instead of object light reflected from a three-dimensional object. Will be recorded a lot. At the time of recording, multiplex recording such as angle multiplexing, phase multiplexing, wavelength multiplexing, and shift multiplexing is performed, so that the capacity can be increased to 1 TB. In addition, a CCD, CMOS, or the like is usually used for reading, and the parallel transfer and reading thereof can increase the transfer rate up to 1 Gbps.

However, the requirements for the hologram recording material used for the holographic memory are more severe than those for three-dimensional displays and HOE applications as described below.
(1) High sensitivity (2) High resolution (3) High diffraction efficiency of hologram (4) Processing during recording is dry and quick (5) Multiple recording is possible (Wide dynamic range)
(6) Shrinkage after recording is small (7) Hologram preservation is good

  In particular, (1) high sensitivity, (3) high diffraction efficiency, (4) dry processing, (6) low shrinkage after recording, and (7) good storage stability. These are physical properties that are contradictory in chemical terms, and it is extremely difficult to achieve both.

  Here, as a known volume phase hologram recording material, a dichromate gelatin method, a bleached silver halide salt method, a photopolymer method, and the like are known as a write-once method, and a photorefractive method and a photochromic polymer as a rewritable method. Methods are known.

However, in these known volume phase hologram recording materials, particularly in the application to high-sensitivity optical recording media, materials that satisfy all of the required requirements are still desired and improvements are desired.
Specifically, for example, the dichromated gelatin method has the advantages of high diffraction efficiency and low noise characteristics, but has extremely poor storage stability, requires wet processing and has low sensitivity, and is suitable for holographic memory applications. Not suitable.
The bleached silver halide method has the advantage of high sensitivity, but it requires wet processing, is complicated in bleaching processing, has problems of large scattering and poor light resistance, and is used for holographic memory applications. After all it is not generally suitable.
Although the photorefractive material has the advantage that it can be rewritten, it has a problem that a high electric field needs to be applied at the time of recording and the record storage stability is poor.
Although the photochromic polymer system represented by azobenzene polymer material has the advantage that it can be rewritten, it has a problem that the sensitivity is very low and the storage stability is poor. For example, International Publication No. WO 97/44365 [Patent Document 4] presents a rewritable hologram recording material using refractive index anisotropy and orientation control of an azobenzene polymer (photochromic polymer). In addition, the quantum yield of azobenzene isomerization is low and the method involves orientation change, so the sensitivity is extremely low. Far from.

Under such circumstances, the dry-processed photopolymer method disclosed in Patent Documents 1 to 3 described above has a basic composition of a binder, a monomer capable of radical polymerization, and a photopolymerization initiator. We have devised a difference in refractive index by using a compound having an aromatic ring or chlorine or bromine on one of the radically polymerizable monomers, and as a result, in the bright part of the interference fringes formed during hologram exposure The monomer can form a refractive index difference by polymerization while the binder gathers in the dark part. Therefore, it can be said that it is a relatively practical method that can achieve both high diffraction efficiency and dry processing.
However, compared with the bleached silver halide method, the sensitivity is about 1/1000, heat-fixing treatment of nearly 2 hours is required to increase the diffraction efficiency, and radical polymerization, so polymerization inhibition by oxygen is inhibited. In addition, there is a problem that the diffraction wavelength and angle at the time of reproduction change due to the shrinkage of the recording material after exposure and fixing, and there is a lack of storage stability because the film is soft. Therefore, the holographic memory application cannot withstand use at all.

Here, in general, cationic polymerization, particularly cationic polymerization accompanied by ring opening of an epoxy compound or the like with respect to radical polymerization, gives less rigidity after polymerization and is not hindered by oxygen to give a rigid film. Therefore, some point out that cationic polymerization is more suitable for holographic memory applications.
For example, in JP-A-5-107999 [Patent Document 5], JP-A-8-16078 [Patent Document 6] and the like, a cationically polymerizable compound (monomer or oligomer) is used instead of a binder, and further a sensitizing dye. , A hologram recording material combining a radical polymerization initiator, a cationic polymerization initiator, and a radical polymerizable compound is disclosed.
In addition, JP-T-2001-523842 [Patent Document 7], JP-T 11-512847 [Patent Document 8] and the like do not use radical polymerization, but include sensitizing dyes, cationic polymerization initiators, and cationic polymerization properties. A hologram recording material using only a compound and a binder is disclosed.
However, although these cation polymerization methods show improvement in shrinkage rate compared to radical polymerization methods, the contradiction is that the sensitivity is lowered, and in practical use, it is considered to be a big problem in terms of transfer rate. . In addition, the diffraction efficiency is lowered, which is considered to be a problem in terms of S / N ratio and multiple recording.
JP-T-2004-537620 [Patent Document 9] discloses a hologram recording material comprising a photoreactive material, a polymer obtained by reacting an NCO-terminated prepolymer and a polyol. JP 2000-250382 A [Patent Document 10] includes a polymer matrix and a photoimageable system containing a photoactive monomer, and the matrix and the photoimageable system are phase-separated, It exhibits a Rayleigh ratio of about 7 × 10 ⁻³ or less in 90 ° light scattering at a wavelength effective for hologram formation, and the polymer matrix can be formed by a polymerization reaction independent of the reaction in which the photoactive monomer is polymerized. Possible recording materials are disclosed. These recording materials are still inadequate, although the shrinkage problem after recording is somewhat improved, and the sensitivity decreases due to the progress of polymerization in the latter stage of multiple recording, requiring a large amount of exposure. There is a problem that the recording characteristics are poor and the multiplicity does not increase.

  As described above, since the photopolymer method is a method involving mass transfer, when considering application to a holographic memory, if the storage property is good and the shrinkage is reduced, the sensitivity decreases (cation polymerization method). On the other hand, if the sensitivity is improved, storage stability and shrinkage deteriorate (radical polymerization method). Further, in order to improve the recording density of the holographic memory, multiplex recording exceeding 50 times and preferably exceeding 100 times is essential. However, in the photopolymer method, since polymerization with mass transfer is used for recording. In contrast to the initial recording speed of multiple recording, the recording speed in the latter stage of multiple recording after the polymerization of many compounds has progressed. By controlling this, the exposure amount is adjusted, and a wide dynamic range is achieved. This is a big problem in practical use.

Such problems of high sensitivity, good storage stability, low shrinkage, dry processing dilemma, and multiple recording characteristics (high recording density) are unavoidable as long as the conventional photopolymer system is used. In addition, it is theoretically difficult to satisfy the requirements for holographic memory using a silver halide method, particularly in terms of dry processing.
Therefore, in order to apply hologram recording materials to holographic memory, such problems are drastically solved, especially high sensitivity and low shrinkage, good storage stability, dry processing, multiple recording characteristics (high recording density) Development of a completely new recording method that can satisfy both of these requirements has been strongly desired.

"Holographic Display", Junpei Uchiuchi, Industrial Books JP-A-6-43634 JP-A-2-3082 Japanese Patent Laid-Open No. 3-50588 International Publication No. WO97 / 44365 Pamphlet Japanese Patent Laid-Open No. 5-107999 JP-A-8-16078 Special table 2001-523842 Japanese National Patent Publication No. 11-512847 JP-T-2004-537620 JP 2000-250382 A

Accordingly, an object of the present invention is to provide high sensitivity and high diffraction efficiency, good storage stability, low shrinkage, dry processing, multiple recording characteristics (high recording performance) that can be applied to high-density optical recording media, three-dimensional displays, holographic optical elements, and the like. It is to provide a hologram recording material capable of achieving both (recording density) and an optical recording medium using the same.

The present invention is as follows.
(1) It has a photorefractive index modulation component and a curable polymer, and the photorefractive index modulation component is 1) color development reaction, 2) latent image color development-chromogen self-sensitized amplification color development reaction, and 3) latent image. By any of the following methods: color development-chromogen sensitized polymerization reaction, 4) orientation change of compound having intrinsic birefringence, 5) dye decolorization reaction, 6) residual decolorization dye latent image-latent image sensitization polymerization reaction A hologram recording material, which is a component for recording interference fringes as refractive index modulation.

  (2) The curable polymer forms a polymer matrix formed by polymerization reaction, and the polymerization reaction includes cationic epoxy polymerization reaction, cationic vinyl ether polymerization reaction, cationic alkenyl ether polymerization reaction, cationic allyl ether polymerization reaction, cationic ketene acetal. Polymerization reaction, Epoxyamine step polymerization reaction, Epoxy mercaptan step polymerization reaction, Unsaturated ester amine step polymerization reaction, Unsaturated ester mercaptan step polymerization reaction, Vinyl-silicon hydride step polymerization reaction, Isocyanate-hydroxyl step polymerization reaction, Isocyanate-amine The hologram recording material as described in (1) above, which is a stepwise polymerization reaction or a polymerization reaction comprising a combination thereof.

(3) The hologram recording material according to (1), wherein the curable polymer includes a reactive polymer and a crosslinking agent, and forms a polymer matrix by a polymerization reaction.
(4) The hologram recording material according to (2) or (3), wherein the polymer matrix is formed by a thermal reaction.
(5) The reaction for forming the polymer matrix is a reaction independent of the photorefractive index modulation reaction of the photorefractive index modulation component, and the photorefractive index modulation component is not reacted during the polymer matrix formation reaction. The hologram recording material according to 2) or (3).
(6) The hologram recording material according to (3), wherein the reactive polymer is a polyol, and the crosslinking agent is an NCO-terminated prepolymer.
(7) The hologram recording material according to (6), wherein an exothermic peak occurs within 12 minutes after mixing the polyol and the NCO-terminated prepolymer.

(8) The hologram recording material according to (6), wherein the polymerization reaction is a polymerization reaction comprising an isocyanate-hydroxyl step polymerization reaction, an isocyanate-amine step polymerization reaction, or a combination thereof.
(9) The hologram recording material according to (6), wherein the NCO-terminated prepolymer comprises a substance selected from aromatic isocyanate, aliphatic isocyanate, or a combination thereof.
(10) The hologram recording material according to (6), wherein the NCO-terminated prepolymer comprises a substance selected from aromatic diisocyanate, hexamethylene diisocyanate, hexamethylene diisocyanate derivatives, or a combination thereof. .
(11) The hologram recording material according to (6), wherein the polyol is a polypropylene oxide polyol.
(12) The hologram recording material according to (6), wherein the polyol is made of polytetramethylene ether diol.
(13) The hologram recording material according to (6), wherein the hologram recording material has a thickness of 200 μm or more and Δn of 3 × 10 ⁻³ or more.

(14) The NCO-terminated prepolymer is biscyclohexylmethane diisocyanate, an NCO-terminated prepolymer formed by the reaction of biscyclohexylmethane diisocyanate and polytetramethylene glycol, butylated hydroxytoluene, and / or hexamethylene diisocyanate. And the polyol contains a polyol of polypropylene oxide and a polyol of polytetramethylene ether, and an exothermic peak occurs within 12 minutes after mixing the polyol and the NCO-terminated prepolymer. The hologram recording material according to (6).
(15) The NCO-terminated prepolymer includes a substance selected from diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and a derivative of hexamethylene diisocyanate, and the polyol includes a polyol of polypropylene oxide, and the polyol The hologram recording material according to (6), wherein an exothermic peak occurs within 12 minutes after mixing the NCO-terminated prepolymer.
(16) The hologram recording material according to (1), wherein the curable polymer is made of a melamine-formaldehyde resin.

(17) It has a light refractive index modulation component and a curable polymer, and the system of the light refractive index modulation component and the curable polymer is phase-separated, and is about 7 × in 90 ° light scattering at a wavelength effective for hologram formation. The hologram recording according to (1), wherein the holographic polymer exhibits a Rayleigh ratio of 10 ⁻³ or less, and is formed by a reaction independent of a light refractive index modulation reaction of the light refractive index modulation component. material.
(18) The above-mentioned 2) latent image color development-color former self-sensitized amplification color development reaction is a method for recording a hologram by at least a hologram exposure to produce a color development body that does not absorb the hologram reproduction light wavelength as a latent image. Unlike the hologram exposure, the chromophore latent image is irradiated with light in the wavelength range where the molar absorption coefficient of the sensitizing dye is 5000 or less, and the chromophore is self-sensitized and amplified to produce a refractive index modulation of the interference fringes. The hologram recording material according to any one of the above (1) to (17), wherein the hologram recording material has a second step of recording as, and is performed by dry processing.

(19) As a compound group capable of hologram recording by the above 1) color development reaction or 2) latent image color development-color-former self-sensitized amplification color development reaction,
1) a sensitizing dye that absorbs light by hologram exposure and generates an excited state; and 2) a dye that can be a color former that has a longer wavelength than the original state and has no absorption at the hologram reproduction light wavelength. An interference fringe recording component that contains a precursor and can record interference fringes using refractive index modulation by color development by electron transfer or energy transfer from a sensitizing dye or color former excited state;
The hologram recording material according to any one of (1) to (17), wherein:
(20) The 3) latent image color development-method for recording a hologram by color development sensitization polymerization reaction includes a first step of producing a color development material that does not absorb at least a hologram reproduction light wavelength as a latent image by hologram exposure; It has a second step of causing polymerization by irradiating light having a wavelength different from that of hologram exposure to a color former latent image and recording interference fringes as refractive index modulation, and performing them by dry processing. The hologram recording material according to any one of (1) to (17).

(21) As a compound group capable of hologram recording according to (20), at least 1) a sensitizing dye that absorbs light and generates an excited state by hologram exposure in the first step,
2) Absorption becomes longer in wavelength from the original state by transferring electrons or energy from the excited state of the sensitizing dye in the first step or from the excited state of the chromophore in the second step. A group of dye precursors which can be a color former having an absorption in a wavelength region having a molar extinction coefficient of 5000 or less and having no absorption in a hologram reproduction light wavelength;
3) A polymerization initiator capable of initiating polymerization of the polymerizable compound by electron transfer or energy transfer from the sensitizing dye excited state in the first step and from the color former excited state in the second step,
4) a polymerizable compound, and 5) a binder,
The hologram recording material according to any one of (1) to (17), wherein:

(22) The compound group capable of holographic recording by 5) dye decoloring reaction, at least,
1) a sensitizing dye that absorbs light by hologram exposure to generate an excited state, and 2) a decolorizable dye or a radical generator, an acid generator, a base generator, and a nucleophile as an interference fringe recording component. Agent, electrophile generator, decolorizer precursor and decolorizable dye consisting of triplet oxygen,
After the sensitizing dye generates an excited state by hologram exposure, energy transfer to the decolorable dye directly or electron transfer to erase the decolorable dye, or energy to the decolorizer precursor A decoloring agent is generated from the decoloring agent precursor by moving or electron transfer, and the decoloring agent decolors the decoloring dye, thereby forming an interference fringe by refractive index modulation. The hologram recording material according to any one of (1) to (17).

  (23) In the method of 6) recording a hologram by residual decolorizable dye latent image-latent image sensitizing polymerization reaction, a sensitizing dye having absorption at the hologram exposure wavelength absorbs light during hologram exposure to generate an excited state. Thereafter, the color erasing is performed by directly transferring energy or electron to the erasable dye described in (22) to erase the erasable dye, or by transferring energy or electron with the decolorizer precursor. A decoloring agent is generated from the agent precursor, and the decoloring agent decolorizes the decolorizable dye, whereby the remaining decolorable dye that has not been decolored becomes a latent image, and the residual By irradiating the decolorable dye latent image with light having a wavelength different from that of hologram exposure, the polymerization initiator is activated by energy transfer or electron transfer to cause polymerization, and the interference fringes are recorded as refractive index modulation. The process The hologram recording material according to any one of (1) to (17), characterized in that.

(24) As a group of compounds capable of hologram recording as described in (23), at least 1) a sensitizing dye that absorbs light and generates an excited state by hologram exposure in the first step, and 2) first. Hologram that can be decolored as a result of direct energy transfer or electron transfer from the excited state of the sensitizing dye in the process of step 1 or as a result of generating a decolorant by energy transfer or electron transfer to the decolorizer precursor A decolorizable dye having a molar extinction coefficient of a reproduction light wavelength of 1000 or less,
3) A decolorizer precursor of a polymerization initiator (possibly 2) capable of initiating polymerization of the polymerizable compound by electron transfer or energy transfer from the remaining decolorizable dye excited state in the second step. )
4) a polymerizable compound, and 5) a binder,
The hologram recording material according to any one of (1) to (17), wherein:

(25) The hologram recording material as described in any one of (1) to (24) above, wherein the hologram recording is a system that cannot be rewritten.
(26) The hologram recording material according to any one of (1) to (24), wherein multiple recording can be performed 10 times or more.
(27) The hologram recording material as described in (26) above, wherein the multiple recording can be performed with the exposure amount being constant throughout the multiple recording.
(28) An optical recording medium comprising the hologram recording material according to any one of (1) to (27).
(29) An optical recording medium, wherein the hologram recording material according to any one of (1) to (27) is stored in a light-shielding cartridge at the time of storage.

  According to the present invention, high sensitivity and high diffraction efficiency applicable to high density optical recording media, three-dimensional displays, holographic optical elements, etc., good storage stability, low shrinkage, dry processing, multiple recording characteristics (high recording characteristics) A hologram recording material capable of achieving both (density) and an optical recording medium using the same are provided.

The hologram recording material of the present invention will be described in detail below.
The hologram recording material of the present invention has a photorefractive index modulation component and a curable polymer, and the photorefractive index modulation component is 1) color development reaction, 2) latent image color development-colored body self-sensitized amplification color development reaction. 3) Latent image color development-colored body sensitized polymerization reaction, 4) Orientation change of compound having intrinsic birefringence, 5) Dye decolorization reaction, 6) Residual color erasable dye latent image-latent image sensitization polymerization reaction It is a component that records interference fringes as refractive index modulation by any method.

The hologram recording material of the present invention is preferably not subjected to wet processing.
The hologram recording material of the present invention is preferably a system that cannot be rewritten. Here, the non-rewritable method is a method of recording by irreversible reaction, and indicates a method in which once recorded data can be stored without being rewritten even if it is overwritten and recorded. Therefore, it is suitable for storing important data that requires long-term storage. However, of course, it is possible to newly record in an area that has not been recorded yet. In that sense, it is generally called “write-once type” or “write-once type”.

The light used for hologram recording of the present invention is preferably any of ultraviolet light, visible light, and infrared light having a wavelength of 200 to 2000 nm, more preferably ultraviolet light or visible light having a wavelength of 300 to 700 nm, and still more preferably. It is visible light of 400 to 700 nm.
Furthermore, the light used for the hologram recording of the present invention is preferably a coherent laser beam (having the same phase and wavelength). The laser used may be any of a solid laser, a semiconductor laser, a gas laser, and a liquid laser. Preferred laser beams include, for example, a 532 nm YAG laser double wave, a 355 nm YAG laser triple wave, and a vicinity of 400 to 415 nm. Semiconductor lasers such as GaN and InGaN, semiconductor lasers such as AlGaInP around 650 to 660 nm, 488 or 515 nm Ar ion laser, 632 or 633 nm He—Ne laser, 647 nm Kr ion laser, 694 nm ruby laser and 636, 634, 538, 534, and 442 nm He—Cd laser.
It is also preferable to use a nanosecond or picosecond order pulse laser.
When the hologram recording material of the present invention is used for an optical recording medium, it is preferable to use a semiconductor laser such as a 532 nm YAG laser double wave, a GaN or InGaN laser near 400 to 415 nm, or an AlGaInP near 650 to 660 nm.
The wavelength of light used for hologram reproduction is preferably the same or longer than the wavelength of light used for hologram exposure (recording), and more preferably the same.

In the hologram recording material of the present invention, after the hologram exposure, a fixing step may be performed by light, heat, or both.
In particular, when an acid proliferating agent or a base proliferating agent is used in the hologram recording material of the present invention, it is preferable to use heating for fixing from the viewpoint of allowing the acid proliferating agent or the base proliferating agent to function effectively.
In the case of light fixing, the entire area of the hologram recording material is irradiated with ultraviolet light or visible light (non-interference exposure). Preferred examples of the light source used include a visible light laser, an ultraviolet light laser, a carbon arc, a high-pressure mercury lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, a tungsten lamp, an LED, and an organic EL.
In the case of thermal fixing, the fixing step is preferably performed at 40 ° C to 160 ° C, more preferably 60 ° C to 130 ° C.
When both photofixing and heat fixing are performed, light and heat may be applied simultaneously, or light and heat may be added separately.

  The refractive index modulation amount at the time of interference fringe recording is preferably 0.00001 to 0.5, and more preferably 0.0001 to 0.3. In addition, it is preferable that the refractive index modulation amount is smaller as the film thickness of the hologram recording material is larger, and it is preferable that the refractive index modulation amount is larger as the film thickness of the hologram recording material is thinner.

The (relative) diffraction efficiency η of the hologram recording material is given by the following equation.
η = Idiff / Io (Formula 1)
Here, Io is the intensity of transmitted light that is not diffracted, and Idiff is the intensity of light that is diffracted (transmission type) or reflected (reflection type). The diffraction efficiency takes any value from 0 to 100%, preferably 30% or more, more preferably 60% or more, and most preferably 80% or more.

The sensitivity of the hologram recording material is generally expressed by the exposure amount per unit area (mJ / cm ² ), and it can be said that the smaller this value, the higher the sensitivity. However, the exposure amount at which time is taken as sensitivity varies depending on documents and patents. When the exposure amount starts recording (refractive index modulation), the exposure amount gives the maximum diffraction efficiency (refractive index modulation). In some cases, the exposure amount giving a diffraction efficiency half that of the maximum diffraction efficiency may be an exposure amount at which the gradient of the diffraction efficiency is maximized with respect to the exposure amount E.
Further, from the Kugelnick's theoretical formula, the refractive index modulation amount Δn for giving a certain diffraction efficiency is inversely proportional to the film thickness d. That is, the sensitivity for giving a certain diffraction efficiency varies depending on the film thickness, and the smaller the refractive index modulation amount Δn is, the thicker the film thickness d is. Therefore, unless conditions such as film thickness are matched, the sensitivity cannot be generally compared.
In the present invention, when the sensitivity is “exposure amount giving half the maximum diffraction efficiency (mJ / cm ² )”, the sensitivity of the hologram recording material of the present invention is, for example, about 10 to 200 μm in film thickness. If, is preferably 2J / cm ² or less, more preferably 1 J / cm ² or less, further preferably 500 mJ / cm ² or less, and most preferably 200 mJ / cm ² or less.

  When the hologram recording material of the present invention is used as an optical recording medium in a holographic memory, a large amount of two-dimensional digital information (referred to as signal light) is recorded using a spatial light modulation element (SLM) such as DMD or LCD. Is preferred. In order to increase the recording density, it is preferable to use multiplex recording. The multiplex recording method includes multiplex recording such as angle multiplex, phase multiplex, wavelength multiplex, and shift multiplex. It is preferable to use shift multiple recording. Also, a CCD or CMOS is preferably used for reading the reproduced two-dimensional data.

When the hologram recording material of the present invention is used in a holographic memory as an optical recording medium, it is essential to perform multiplex recording in order to improve the capacity (recording density). At that time, it is more preferable to perform multiplex recording 10 times or more, more preferably 50 times or more, and most preferably 100 times or more. Further, it is more preferable from the viewpoints of simplifying the recording system, improving the S / N ratio, etc. that the exposure amount in the multiple recording can be kept constant throughout the multiple recording.

  When the hologram recording material of the present invention is used for an optical recording medium, it is preferable that the hologram recording material during storage is stored in a light shielding cartridge. In addition, a light shielding filter capable of cutting a part of the wavelength range of ultraviolet light, visible light, and infrared light other than the recording light and reproduction light wavelengths may be provided on the front surface, back surface, or both surfaces of the hologram recording material. preferable.

  When the hologram recording material of the present invention is used for an optical recording medium, the optical recording medium may be disk-shaped, card-shaped, tape-shaped, or any shape.

  The optical refractive index modulation component of the present invention and a hologram recording method using the same will be described in detail below.

1) Interference fringe recording by color development reaction In the present invention, the color development reaction indicates a reaction in which the absorption spectrum shape changes in the region of ultraviolet light, visible light and infrared light of 200 to 2000 nm, more preferably In the absorption spectrum, it shows a reaction in which either λmax becomes longer wavelength or ε increases, and more preferably, a reaction in which both occur. Moreover, it is more preferable that the color development reaction occurs in a wavelength region of 200 to 1000 nm, and it is more preferable that the color development reaction occurs in a wavelength region of 300 to 900 nm.

When recording is based on a color development reaction, the hologram recording material of the present invention is preferably
at least,
1) a sensitizing dye that absorbs light by hologram exposure and generates an excited state;
2) including a dye precursor that can be a color former whose absorption is increased from the original state and has no absorption at the hologram reproduction light wavelength, and by electron transfer or energy transfer from the sensitizing dye excited state, It is preferable to include an interference fringe recording component capable of recording an interference fringe using refractive index modulation by color development.

Here, the refractive index of the dye generally takes a high value from the vicinity of the linear absorption maximum wavelength (λmax) in a region having a longer wavelength than that, and particularly takes a very high value in a region having a wavelength as long as 200 nm from λmax to λmax, Some dyes have high values exceeding 1.8 and in some cases exceeding 2. On the other hand, organic compounds that are not pigments such as binder polymers usually have a refractive index of about 1.4 to 1.6.
Therefore, it can be seen that coloring the dye precursor by hologram exposure can preferably form not only an absorptivity difference but also a large refractive index difference.
The hologram recording material of the present invention is preferably a phase-type hologram recording material that records interference fringes by refractive index modulation in terms of high diffraction efficiency. That is, at the time of hologram reproduction, it is preferable that the hologram recording material has no absorption or little absorption at the reproduction light wavelength.
Therefore, when the dye precursor of the present invention becomes a color former after hologram exposure, it is preferable that the color precursor does not have absorption at the hologram recording and reproduction wavelength but has absorption at a shorter wavelength side than that. . The sensitizing dye is preferably decomposed during hologram recording or subsequent fixing to lose its absorption and sensitizing functions.

  Furthermore, in order to increase the refractive index modulation and increase the sensitivity and dynamic range, the dye precursor of the present invention has no absorption at the hologram recording and reproduction wavelength after hologram exposure, and from the hologram recording wavelength and the hologram recording wavelength. It is preferable to be a color former having an absorption maximum in a region between wavelengths of 200 nm short wavelength, and to be a color body having an absorption maximum in a region between the hologram recording wavelength and a wavelength of 100 nm short wavelength from the hologram recording wavelength. Is more preferable.

  First, the sensitizing dye that absorbs light and generates an excited state in the hologram exposure of the present invention will be described in detail.

  The sensitizing dye of the present invention preferably generates an excited state by absorbing any of ultraviolet light, visible light, and infrared light having a wavelength of 200 to 2000 nm, more preferably ultraviolet light having a wavelength of 300 to 700 nm. It absorbs light or visible light to generate an excited state, and more preferably absorbs visible light of 400 to 700 nm to generate an excited state.

The sensitizing dye of the present invention is preferably a cyanine dye, squarylium cyanine dye, styryl dye, pyrylium dye, merocyanine dye, benzylidene dye, oxonol dye, azurenium dye, coumarin dye, ketocoumarin dye, styrylcoumarin dye, pyran dye, xanthene dye. Thioxanthene dye, phenothiazine dye, phenoxazine dye, phenazine dye, phthalocyanine dye, azaporphyrin dye, porphyrin dye, fused ring aromatic dye, perylene dye, azomethine dye, anthraquinone dye, metal complex dye, metallocene dye, etc. And more preferably cyanine dyes, squarylium cyanine dyes, pyrylium dyes, merocyanine dyes, oxonol dyes, coumarin dyes, ketocoumarin dyes, styryl coumarin dyes. Pyran dyes, xanthene dyes, thioxanthene dyes, condensed aromatic dyes, metal complex dyes, include metallocene dyes, more preferred are cyanine dyes, merocyanine dyes, oxonol dyes, metal complex dyes, metallocene dyes. As the metal complex dye, a Ru complex dye is particularly preferable, and as the metallocene dye, ferrocenes are particularly preferable.
In addition, “Dye Handbook” (Shin Okawara et al., Kodansha 1986), “Chemistry of Functional Dye” (Shin Okawara et al. CMC 1981), “Special Functional Materials” (Chemical Icmori Others CMC 1986) The dyes and dyes described in 1) can also be used as the sensitizing dye of the present invention. The sensitizing dye of the present invention is not limited to these, and any dye and dye that absorbs visible light can be used. These sensitizing dyes can be selected in accordance with the wavelength of the laser serving as a light source according to the purpose of use, and two or more kinds of sensitizing dyes may be used in combination depending on the application.

  Since the hologram recording material is used in a thick film and most of the recording light needs to pass through the film, the addition amount of the sensitizing dye is increased as much as possible by reducing the molar extinction coefficient of the sensitizing dye at the hologram exposure wavelength. It is preferable to increase the sensitivity. The molar extinction coefficient of the sensitizing dye at the hologram exposure wavelength is preferably 1 or more and 10,000 or less, more preferably 1 or more and 5000 or less, further preferably 5 or more and 2500 or less, and more preferably 10 or more and 1000 or less. Most preferred.

  The recording wavelength light transmittance of the hologram recording material is preferably 10 to 99%, more preferably 20 to 95%, further preferably 30 to 90%, and 40 to 85%. It is most preferable in terms of diffraction efficiency, sensitivity, and recording density (multiplicity). Therefore, it is preferable to adjust the molar extinction coefficient and the added molar concentration at the recording wavelength of the sensitizing dye in accordance with the film thickness of the hologram recording material so as to be like that.

  Further, λmax of the sensitizing dye is preferably shorter than the hologram recording wavelength, and more preferably in the range from the same as the hologram recording wavelength to a wavelength shorter than 100 nm.

Further, the molar extinction coefficient at the recording wavelength of the sensitizing dye is preferably 1/5 or less of the molar extinction coefficient of λmax, and more preferably 1/10 or less.
In particular, when the sensitizing dye is an organic dye such as a cyanine dye or a merocyanine dye, it is preferably 1/20 or less, more preferably 1/50 or less, and 1/100 or less. Is most preferred.
Specific examples of the sensitizing dye of the present invention are given below, but the present invention is not limited thereto.

  In the case of a YAG laser double wave with a hologram recording wavelength of 532 nm, the sensitizing dye is particularly preferably a trimethine cyanine dye having a benzoxazole ring, a Ru complex dye, or ferrocenes, such as GaN or InGaN having a wavelength of 400 to 415 nm. In the case of a laser, a monomethine cyanine dye having a benzoxazole ring, a Ru complex dye, and ferrocenes are particularly preferable.

  Other preferred examples of the sensitizing dye of the present invention are described in Japanese Patent Application No. 2004-238427. The sensitizing dye of the present invention is a commercial product, or can be synthesized by a known method.

  As the interference fringe recording component, the following combinations are preferable. About these, the example described in Japanese Patent Application No. 2004-238077 is mentioned preferably as a specific example.

i) A combination comprising at least an acid color-forming dye precursor as a dye precursor and an acid generator. A combination further containing an acid proliferating agent if necessary.
As the acid generator, diaryl iodonium salts, sulfonium salts and sulfonic acid esters are preferable, and the above-described acid generator (cationic polymerization initiator) can be preferably used.
The color former generated from the acid color-formable dye precursor is preferably a xanthene dye, a fluorane dye or a triphenylmethane dye. Particularly preferred specific examples of the acid coloring dye precursor are listed below, but the present invention is not limited thereto.

  In addition, as the acid color-forming dye precursor of the present invention, a cyanine base (leucocyanine dye) that develops color by addition of an acid (proton) is also preferably used. Although the preferable example of a cyanine base is shown below, this invention is not necessarily limited to this.

ii) A combination containing at least a base color-forming dye precursor as a dye precursor, a base generator, and a base proliferating agent as necessary.
As the base generator, the above-mentioned base generator (anionic polymerization initiator) is preferably mentioned, and as the base color-forming dye precursor, dissociable azo dye, dissociable azomethine dye, dissociable oxonol dye, dissociable xanthene dye , Dissociated fluorane dyes, and non-dissociated isomers of dissociated triphenylmethane dyes.
Particularly preferred specific examples of the base color-forming dye precursor are listed below, but the present invention is not limited thereto.

  iii) an organic compound moiety having a function of cleaving a covalent bond by electron transfer or energy transfer with a sensitizing dye excited state, and an organic compound moiety having a characteristic of becoming a color former when covalently bonded and released Contains a covalently bonded compound. A combination further containing a base if necessary. Particularly preferred specific examples are listed below, but the present invention is not limited thereto.

iv) When a compound that reacts by electron transfer with the sensitizing dye excited state and can change the absorption form is included. So-called electrochromic compounds can be preferably used.
Further, it is more preferable to include a curable polymer (binder polymer). As the binder polymer, 3) Examples described later in the section of interference fringe recording by latent image color development-coloring body sensitization polymerization reaction, and Japanese Patent Application No. 2004-2004 Preferred examples include those described in US Pat. No. 2,380,77, and particularly preferred binder polymers for the present invention described below.

2) Latent image color development—Interference fringe recording by self-sensitized amplification color development reaction of color former Preferably, at least a first step of producing a color former that does not absorb the hologram reproduction light wavelength as a latent image by hologram exposure, and its color development Unlike hologram exposure, the body latent image is irradiated with light in the wavelength range where the molar absorption coefficient of the sensitizing dye is 5000 or less, and the colored body is self-sensitized and amplified, thereby recording the interference fringes as refractive index modulation. The hologram recording method is characterized by having two steps and performing them by dry processing, and is preferable in terms of high-speed writing, high S / N ratio reproduction, and the like.

  Here, the “latent image” means “a refractive index difference that is preferably half or less of a refractive index difference formed after the second step” (that is, preferably doubled in the second step). The above-described amplification process is performed), and the refractive index difference image is more preferably 1/5 or less, more preferably 1/10 or less, and most preferably 1/3 or less (that is, the second difference image). The amplification step is more preferably 5 times or more, more preferably 10 times or more, and most preferably 30 times or more.

Here, the second step is preferably light irradiation, heat application, or both, more preferably light irradiation, and the light to be irradiated is the entire surface exposure (so-called solid exposure, blanket exposure, non-image). Wise exposure) is preferable.
Preferred examples of the light source used include a visible light laser, an ultraviolet light laser, an infrared light laser, a carbon arc, a high pressure mercury lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, a tungsten lamp, an LED, and an organic EL. In order to irradiate light in a specific wavelength region, it is also preferable to use a sharp cut filter, a band pass filter, a diffraction grating, or the like as necessary.

Furthermore, as a hologram recording material capable of such a hologram recording method, at least,
1) a sensitizing dye that absorbs light by hologram exposure and generates an excited state;
2) Includes a dye precursor that can be a color former that has a longer wavelength than the original state and that has no absorption at the hologram reproduction light wavelength, and moves electrons or energy from the sensitized dye or color former excited state. Interference fringe recording component capable of recording interference fringes using refractive index modulation by color development,
It is preferable to contain.
Preferred examples of the sensitizing dye and the interference fringe recording component are the same as those described in 1) Color development reaction.
In the wavelength range of the light irradiated in the second step, the molar absorption coefficient of linear absorption of the sensitizing dye is more preferably 1000 or less, and further preferably 500 or less.
In the wavelength range of the light irradiated in the second step, it is preferable that the molar extinction coefficient of the color former is 1000 or more.

The concept of “latent image color development—colored body self-sensitized amplification color reaction system” will be described below.
For example, a hologram recording material is irradiated with a 532 nm YAG / SHG laser and absorbed by a sensitizing dye to generate an excited state. By transferring energy or electrons from the excited state of the sensitizing dye to the interference fringe recording component, the dye precursor contained in the interference fringe recording component is changed to a color former to form a latent image by color development (the first is described above). Process). Next, light in a wavelength region of 350 to 420 nm is irradiated to cause the color former to be absorbed, and the color former is amplified and generated by self-sensitization of the color former (the second step). In the first step, a latent image is not generated so much in the portion that is the interference dark portion, so that the self-sensitizing color reaction hardly occurs in the second step, and as a result, a large refractive index modulation is performed in the interference bright portion and the interference dark portion. Can be formed and recorded as interference fringes. For example, when a 532 nm laser is used again to irradiate the recorded hologram recording material, the recorded information, images, etc. can be reproduced or function as a desired optical material.

  As a specific example of the latent image color development-chromogen self-sensitized amplification color development reaction, an example described in Japanese Patent Application No. 2004-238427 is preferable.

3) Latent Image Coloring—Interference fringe recording by chromogenic sensitization polymerization reaction Preferably, at least a first step of generating a color developing material having no absorption at the wavelength of the hologram reproduction light as a latent image by hologram exposure, and the color forming latent image Hologram recording characterized in that it has a second process of recording an interference fringe as a refractive index modulation by irradiating the image with light having a wavelength different from that of hologram exposure, and recording the interference fringes as refractive index modulation. This method is excellent in high-speed writing and storage stability.
In the second step, a method in which polymerization is caused while self-sensitizing amplification production is performed is also preferable.

Furthermore, as a hologram recording material capable of such a hologram recording method, at least,
1) a sensitizing dye that absorbs light and generates an excited state by hologram exposure in the first step;
2) Absorption becomes longer in wavelength from the original state by transferring electrons or energy from the excited state of the sensitizing dye in the first step or from the excited state of the chromophore in the second step. A group of dye precursors which can be a color former having an absorption in a wavelength region having a molar extinction coefficient of 5000 or less and having no absorption in a hologram reproduction light wavelength;
3) A polymerization initiator capable of initiating polymerization of the polymerizable compound by electron transfer or energy transfer from the sensitizing dye excited state in the first step and from the color former excited state in the second step,
4) a polymerizable compound, and 5) a binder,
It is preferable to contain.
Preferred examples of the sensitizing dye and the interference fringe recording component are the same as those described in 1) Color development reaction.

  Preferred examples of the polymerization initiator, the polymerizable compound and the binder are described in detail below.

In recording interference fringes by a polymerization reaction, the binder preferably has a refractive index different from that of the polymerizable compound. In order to increase the refractive index modulation, the refractive index difference in the bulk of the polymerizable compound and the binder is preferably large, and the refractive index difference is preferably 0.01 or more, more preferably 0.05 or more. Preferably, it is 0.1 or more.
For this purpose, either the polymerizable compound or the binder contains at least one aryl group, aromatic heterocyclic group, chlorine atom, bromine atom, iodine atom or sulfur atom, and the other one contains them. Preferably not. It does not matter whether the polymerizable compound has a higher refractive index or the binder has a higher refractive index.

The polymerizable compound of the present invention is a radical, acid (Bronsted acid or Lewis acid) or base (Bronsted base or Lewis base) generated by irradiating light to a sensitizing dye (or color former) and a polymerization initiator. ) Is a compound capable of undergoing addition polymerization to be oligomerized or polymerized.
The polymerizable compound of the present invention may be monofunctional or polyfunctional, may be a single component or a multicomponent, and may be a monomer, a prepolymer (eg, a dimer or oligomer), or a mixture thereof, but is a monomer. It is preferable.
The form may be liquid or solid at room temperature, but it is preferably a liquid having a boiling point of 100 ° C. or higher, or a mixture of a liquid monomer having a boiling point of 100 ° C. or higher and a solid monomer. .

The polymerizable compound of the present invention is roughly classified into a polymerizable compound capable of radical polymerization and a polymerizable compound capable of cationic or anionic polymerization.
In the following, for each of the polymerizable compound capable of radical polymerization and the polymerizable compound capable of cationic or anion polymerization, A) refractive index: polymerizable compound> binder, and B) refractive index: binder> polymerizable compound. In particular, examples of preferable polymerizable compounds will be described.

    A) Refractive index: Polymerizable compound> Preferred examples of radical polymerizable compound in the case of binder

  In this case, the radical polymerizable compound preferably has a high refractive index, and the high refractive index radical polymerizable compound of the present invention has at least one ethylenically unsaturated double bond in the molecule, and at least 1 A compound containing at least one aryl group, aromatic heterocyclic group, chlorine atom, bromine atom, iodine atom or sulfur atom is preferred, and a liquid having a boiling point of 100 ° C. or more is preferred.

  Specific examples thereof include the following polymerizable monomers and prepolymers (dimers, oligomers, etc.) comprising them.

  As the high refractive index radical polymerizable monomer, styrene, 2-chlorostyrene, 2-bromostyrene, methoxystyrene, phenyl acrylate, p-chlorophenyl acrylate, 2-phenylethyl acrylate, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, 2- (p-chlorophenoxy) ethyl acrylate, benzyl acrylate, 2- (1-naphthyloxy) ethyl acrylate, 2,2-di (p-hydroxyphenyl) propane diacrylate or di Methacrylate, di (2-methacryloxyethyl) ether of bisphenol-A, di (2-acryloxyethyl) ether of bisphenol-A, di (2-methacryloxyethyl) ether of tetrachloro-bisphenol-A, tetrabromo-bisphenol Di- (2-methacryloxyethyl) ether of Ru-A, 1,4-benzenediol dimethacrylate, 1,4-diisopropenylbenzene, and the like, more preferably 2-phenoxyethyl acrylate, methacrylic acid 2 -Phenoxyethyl, 2- (p-chlorophenoxy) ethyl acrylate, p-chlorophenyl acrylate, phenyl acrylate, 2-phenylethyl acrylate, bisphenol-A di (2-acryloxyethyl) ether, acrylic acid 2 -(1-naphthyloxy) ethyl and the like.

  Preferred polymerizable compounds are liquids, but they are N-vinyl carbazole, 2-naphthyl acrylate, pentachlorophenyl acrylate, 2,4,6-tribromophenyl acrylate, bisphenol-A diacrylate, 2-acrylate acrylate. It may be used in admixture with (2-naphthyloxy) ethyl and a second solid polymerizable compound such as N-phenylmaleimide.

  B) Refractive index: Preferable example of radically polymerizable compound in the case of binder> polymerizable compound

In this case, the radical polymerizable compound preferably has a low refractive index, and the low refractive index radical polymerizable compound of the present invention has at least one ethylenically unsaturated double bond in the molecule, and further has an aryl group. It is preferable that no aromatic heterocyclic group, chlorine atom, bromine atom, iodine atom or sulfur atom is contained.
Moreover, it is preferable that it is a liquid whose boiling point is 100 degreeC or more.
Specific examples thereof include the following polymerizable monomers and prepolymers (dimers, oligomers, etc.) comprising them.

The low refractive index radical polymerizable monomer is preferably t-butyl acrylate, cyclohexyl acrylate, iso-bornyl acrylate, 1,5-pentanediol diacrylate, ethylene glycol diacrylate, 1,4-butanediol diacrylate, Diethylene glycol diacrylate, hexamethylene glycol diacrylate, 1,3-propanediol diacrylate, decamethylene glycol diacrylate, 1,4-cyclohexyldiol diacrylate, 2,2-dimethylolpropane diacrylate, glycerol diacrylate, trimethylol Propane diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, triethylene glycol diacrylate, trie Lenglycol dimethacrylate, ethylene glycol dimethacrylate, 1,3-propanediol dimethacrylate, 1,2,4-butanetriol trimethacrylate, 2,2,4-trimethyl-1,3-propanediol dimethacrylate, pentaerythritol tri Methacrylate, pentaerythritol tetramethacrylate, trimethylolpropane trimethacrylate, 1,5-pentanediol dimethacrylate, diallyl fumarate, acrylic acid 1H, 1H-perfluorooctyl,
Examples thereof include 1H, 1H, 2H, 2H-perfluorooctyl methacrylate, 1H, 1H, 2H, 2H-perfluorooctyl acrylate, 1-vinyl-2-pyrrolidinone, and more preferably decanediol diacrylate and acrylic. Examples include acid iso-bornyl, triethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, ethoxyethoxyethyl acrylate, triacrylate ester of ethoxylated trimethylolpropane, and 1-vinyl-2-pyrrolidine. More preferably, decanediol diacrylate, iso-bornyl acrylate, triethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate , Ethoxyethoxyethyl acrylate, 1H, 1H-perfluorooctyl acrylate, 1H, 1H, 2H, 2H-perfluorooctyl methacrylate, 1H, 1H, 2H, 2H-perfluorooctyl acrylate, 1-vinyl-2 -Pyrrolidine etc. are mentioned.

  The preferred polymerizable compounds are liquids, but they may be used in admixture with a second solid polymerizable compound monomer such as N-vinylcaprolactam.

  The cationic polymerizable compound of the present invention is a compound that is polymerized by an acid generated by irradiating light to a sensitizing dye and a cationic polymerization initiator. The anionic polymerizable compound of the present invention is a sensitizing dye and an anionic polymerization. It is a compound in which polymerization is initiated by a base generated by irradiating the initiator with light.

The cation polymerizable compound of the present invention is preferably a compound having at least one oxirane ring, oxetane ring, vinyl ether group, styryl group or N-vinyl carbazole moiety in the molecule, more preferably a compound having an oxirane ring moiety. It is.
The anionic polymerizable compound of the present invention is preferably an oxirane ring, an oxetane ring, a vinyl ether group, a styryl group, an N-vinylcarbazole moiety, an ethylenic double bond moiety having an electron-withdrawing substituent, a lactone moiety, a lactam moiety, A compound having at least one cyclic urethane moiety, cyclic urea moiety or cyclic siloxane moiety in the molecule, more preferably a compound having an oxirane ring moiety.

  A) Refractive index: Polymerizable compound> Preferred examples of cationic or anionic polymerizable compound in the case of binder

  In this case, the cation or anion polymerizable compound preferably has a high refractive index, and the high refractive index cation or anion polymerizable compound of the present invention includes at least one oxirane ring, oxetane ring, vinyl ether group, styryl group, N -A compound having a vinylcarbazole moiety in the molecule and further containing at least one aryl group, aromatic heterocyclic group, chlorine atom, bromine atom, iodine atom or sulfur atom is preferred, and at least one aryl group It is preferable to contain. Moreover, it is preferable that it is a liquid whose boiling point is 100 degreeC or more.

  Specific examples thereof include the following polymerizable monomers and prepolymers (dimers, oligomers, etc.) comprising them.

Preferred as a high refractive index cationic or anionic polymerizable monomer having an oxirane ring is phenyl glycidyl ether, phthalic acid diglycidyl ester, trimellitic acid triglycidyl ester, resorcin diglycidyl ether, dibromophenyl glycidyl ether, dibromoneopentyl glycol diglycidyl ether 4,4′-bis (2,3-epoxypropoxyperfluoroisopropyl) diphenyl ether, p-bromostyrene oxide, bisphenol-A-diglycidyl ether, tetrabromobisphenol-A-diglycidyl ether, bisphenol-F-diglycidyl Ether, 1,3
-Bis (3 ', 4'-epoxycyclohexyl) ethyl) -1,3, -diphenyl-1,3, -dimethyldisiloxane and the like.

  Specific examples of the high refractive index cation or anion polymerizable monomer having an oxetane ring include compounds in which the oxirane ring in the specific examples of the high refractive index cation or anion polymerizable monomer having an oxirane ring is replaced with an oxetane ring. It is done.

  Specific examples of the high refractive index cation or anion polymerizable monomer having a vinyl ether group moiety include, for example, vinyl-2-chloroethyl ether, 4-vinyl ether styrene, hydroquinone divinyl ether, phenyl vinyl ether, bisphenol A divinyl ether, and tetrabromobisphenol A. Examples thereof include divinyl ether, bisphenol F divinyl ether, phenoxyethylene vinyl ether, and p-bromophenoxyethylene vinyl ether.

  In addition, styrene monomers such as styrene, 2-chlorostyrene, 2-bromostyrene, methoxystyrene, and N-vinylcarbazole are also preferable as the high refractive index cationic polymerizable monomer.

  B) Refractive index: Preferable example of cationic or anionic polymerizable compound in the case of binder> polymerizable compound

  In this case, the cation or anion polymerizable compound preferably has a low refractive index, and the low refractive index cation or anion polymerizable compound of the present invention has at least one oxirane ring, oxetane ring, or vinyl ether group in the molecule. Furthermore, a compound containing no aryl group, aromatic heterocyclic group, chlorine atom, bromine atom, iodine atom or sulfur atom is preferred. Moreover, it is preferable that it is a liquid whose boiling point is 100 degreeC or more.

  Specific examples thereof include the following polymerizable monomers and prepolymers (dimers, oligomers, etc.) comprising them.

  Specific examples of the low refractive index cation or anion polymerizable monomer having an oxirane ring include glycerol diglycidyl ether, glycerol triglycidyl ether, pentaerythritol polyglycidyl ether, trimethylolpropane triglycidyl ether, 1,6-hexanediol. Diglycidyl ether, ethylene glycol diglycidyl ether, ethylene glycol monoglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, adipic acid diglycidyl ester, 1,2,7,8-diepoxyoctane, 1, 6-dimethylol perfluorohexane diglycidyl ether, vinylcyclohexene dioxide, 3,4-epoxycyclohexylmethyl-3 ′, 4 -Epoxycyclohexanecarboxylate, 3,4-epoxycyclohexyloxirane, bis (3,4-epoxycyclohexyl) adipate, 2,2-bis [4- (2,3-epoxypropoxy) cyclohexyl] propane, 2,2-bis [4- (2,3-epoxypropoxy) cyclohexyl] hexafluoropropane, 2- (3,4-epoxycyclohexyl) -3 ′, 4′-epoxy-1,3-dioxane-5-spirocyclohexane, 1,2 -Ethylenedioxy-bis (3,4-epoxycyclohexylmethane), ethylene glycol-bis (3,4-epoxycyclohexanecarboxylate), bis- (3,4-epoxycyclohexylmethyl) adipate, di-2,3- Epoxy cyclopentyl ether, vinyl grease Jill ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, 1,3-bis (3 ', 4'-epoxycyclohexyl) ethyl) -1,1,3,3, - tetramethyl disiloxane and the like.

  Specific examples of the low refractive index cation or anion polymerizable monomer having an oxetane ring include compounds in which the oxirane ring in the specific examples of the low refractive index cation or anion polymerizable monomer having an oxirane ring is replaced with an oxetane ring. It is done.

  Specific examples of the low refractive index cationic or anionic polymerizable monomer having a vinyl ether group moiety include, for example, vinyl-n-butyl ether, vinyl t-butyl ether, ethylene glycol divinyl ether, ethylene glycol monovinyl ether, propylene glycol divinyl ether, neo Pentyl glycol divinyl glycol, glycerol divinyl ether, glycerol trivinyl ether, triethylene glycol divinyl ether, trimethylolpropane monovinyl ether, trimethylolpropane divinyl ether, trimethylolpropane trivinyl ether, allyl vinyl ether, 2,2-bis (4-cyclohexanol ) Propane divinyl ether, 2,2-bis (4-cyclohexanol) trifluoro Propane divinyl ether.

  Next, preferred binders in the present invention at the time of interference fringe recording by polymerization reaction are divided into the case of A) refractive index: polymerizable compound> binder and B) refractive index: binder> polymerizable compound. An example will be described.

  A) Preferred examples of binders in the case of refractive index: polymerizable compound> binder.

In this case, the binder preferably has a low refractive index, and is preferably a binder containing no aryl group, aromatic heterocyclic group, chlorine atom, bromine atom, iodine atom, or sulfur atom.
Specific examples of preferred low refractive index binders include acrylate and alpha-alkyl acrylate esters and acidic polymers and interpolymers (eg, polymethyl methacrylate and polyethyl methacrylate, methyl methacrylate and other (meth) acrylic acid alkyl esters). Copolymers), polyvinyl esters (eg, polyvinyl acetate, polyacetic acid / vinyl acrylate, polyacetic acid / vinyl methacrylate and hydrolyzable polyvinyl acetate), ethylene / vinyl acetate copolymers, saturated and unsaturated polyurethanes, Butadiene and isoprene polymers and copolymers and polyglycol high molecular weight poly (ethylene oxide) having an average molecular weight of approximately 4,000 to 1,000,000, epoxides (e.g. Product), polyamide (for example, N-methoxymethyl polyhexamethylene adipamide), cellulose ester (for example, cellulose acetate, cellulose acetate succinate and cellulose acetate butyrate), cellulose ether (for example, methyl cellulose, ethyl cellulose, ethyl benzyl cellulose) ), Polycarbonate, polyvinyl acetal (for example, polyvinyl butyral and polyvinyl formal), polyvinyl alcohol, polyvinyl pyrrolidone, and the like.

  A fluorine atom-containing polymer is also preferable as the low refractive index binder. Preferably, fluoroolefin is an essential component, and one or more selected from alkyl vinyl ether, alicyclic vinyl ether, hydroxy vinyl ether, olefin, haloolefin, unsaturated carboxylic acid and ester thereof, and carboxylic acid vinyl ester It is a polymer soluble in an organic solvent having the unsaturated monomer as a copolymerization component. The mass average molecular weight is preferably 5,000 to 200,000, and the fluorine atom content is preferably 5 to 70% by mass.

Specific examples of the aforementioned fluorine atom-containing polymer include, for example, an organic solvent-soluble “Lumiflon” series having a hydroxyl group (for example, Lumiflon LF200, mass average molecular weight: about 50,000, manufactured by Asahi Glass Co., Ltd.). In addition, Daikin Industries, Ltd., Central Glass (
Co., Ltd., Penwort Co., Ltd., etc. have also marketed organic solvent-soluble fluorine atom-containing polymers, which can also be used.

In addition, preferred examples include silicon compounds such as poly (dimethylsiloxane) and silicon oils not containing aromatics.
In addition, an epoxy oligomer compound containing no aromatic can also be used as a low refractive index reactive binder.

  B) Refractive index: A preferred example of a binder in the case of binder> polymerizable compound.

In this case, the binder preferably has a high refractive index, and is preferably a binder containing at least one aryl group, aromatic heterocyclic group, chlorine atom, bromine atom, iodine atom, or sulfur atom. More preferably, the binder contains.
Specific examples of preferable high refractive index binders include polystyrene polymers and copolymers such as acrylonitrile, maleic anhydride, acrylic acid, methacrylic acid and esters thereof, and vinylidene chloride copolymers (eg, vinylidene chloride / acrylonitrile copolymer). Polymer, vinylidene chloride / methacrylate copolymer, vinylidene chloride / vinyl acetate copolymer), polyvinyl chloride and copolymers (eg, polyvinyl chloride / acetate, vinyl chloride / acrylonitrile copolymer), polyvinyl benzal synthetic rubber (For example, butadiene / acrylonitrile copolymer, acrylonitrile / butadiene / styrene copolymer, methacrylate / acrylonitrile / butadiene / styrene copolymer, 2-chlorobutadiene-1,3 polymer, chlorinated rubber, On / butadiene / styrene, styrene / isoprene / styrene block copolymer), copolyesters (e.g., formula HO (CH ₂₎ polymethylene glycol nOH (n in the formula is an integer of 2 to 10) and, ( 1) produced from reaction products of hexahydroterephthalic acid, sebacic acid and terephthalic acid, (2) terephthalic acid, isophthalic acid and sebacic acid, (3) terephthalic acid and sebacic acid, (4) terephthalic acid and isophthalic acid And (5) mixtures of the glycols and (i) terephthalic acid, isophthalic acid and sebacic acid and (ii) copolyesters made from terephthalic acid, isophthalic acid, sebacic acid and adipic acid), poly N-vinylcarbazole And its copolymer, polycarbonate comprising carbonate and bisphenol Such as over doors and the like.

Preferable examples include poly (methylphenylsiloxane), silicon compounds such as 1,3,5-trimethyl-1,1,3,5,5-pentaphenyltrisiloxane, silicon oil containing a large amount of aromatics, and the like. .
In addition, an epoxy oligomer compound containing a large amount of aromatics can also be used as a high refractive index reactive binder.

  The polymerization initiator used for interference fringe recording by the polymerization reaction of the present invention is preferably a ketone, an organic peroxide, a trihalomethyl-substituted triazine, a diazonium salt, a diaryliodonium salt, a sulfonium salt, or a borate. Radical polymerization of diaryl iodonium organoboron complex, sulfonium organoboron complex, cationic sensitizing dye organoboron complex, anionic sensitizing dye onium salt complex, metal arene complex, sulfonate ester An agent (radical generator) or a cationic polymerization initiator (acid generator), or a compound having both functions.

  At that time, it is also preferable to use an acid proliferating agent from the viewpoint of high sensitivity. Specific examples of preferred acid proliferating agents include those described in Japanese Patent Application No. 2003-182849.

Further, it is also preferable to use anionic polymerization and an anionic polymerization initiator (base generator). In that case, it is also preferable to use a base proliferating agent from the viewpoint of high sensitivity. In those cases, specific examples of the anionic polymerization initiator and the base proliferating agent include those described in Japanese Patent Application No. 2003-178083.

  Specific examples of preferred polymerization initiators, polymerizable compounds and binders of the present invention include those described in Japanese Patent Application No. 2004-238392.

  Specific examples of preferred polymerization initiators in the present invention are listed below, but the present invention is not limited thereto.

In the wavelength range of the light irradiated in the second step, the molar absorption coefficient of linear absorption of the sensitizing dye is more preferably 1000 or less, and further preferably 500 or less.
In the wavelength range of the light irradiated in the second step, it is more preferable that the molar extinction coefficient of the color former is 1000 or more.

  In the hologram recording material of the present invention, it is preserved that the sensitizing dye is decomposed and fixed by either the first step, the second step, or the subsequent fixing step by light irradiation, heat application, or both. From the viewpoint of the property and non-destructive regeneration, and further, the sensitizing dye is added by either the first step, the second step, or the fixing step by subsequent light irradiation, heat application, or both. More preferably, the colored body is decomposed and fixed by either the process or the fixing process by light irradiation, heat application, or both.

The concept of “latent image color development-colored material sensitized polymerization reaction system” will be described below.
For example, a hologram recording material is irradiated with a 532 nm YAG / SHG laser and absorbed by a sensitizing dye to generate an excited state. By transferring energy or electrons from the excited state of the sensitizing dye to the interference fringe recording component, the dye precursor contained in the interference fringe recording component is changed to a color former to form a latent image by color development (the first is described above). Process). Next, light in the wavelength region of 350 to 420 nm is irradiated to cause the color former to be absorbed, and the polymerization initiator is activated by electron transfer or energy transfer to initiate polymerization. For example, when the polymerizable compound has a higher refractive index than the binder, the refractive index increases because the polymerizable compound collects in the portion where the polymerization occurs (second step). In the first step, the latent image is not generated so much in the portion that is the interference dark portion, so polymerization does not occur much in the second step, and the abundance ratio of the binder is high, and as a result, the refraction is large in the interference bright portion and the interference dark portion Rate modulation can be formed and recorded as interference fringes. If the sensitizing dye and the color-developing material can be decomposed and decolored by the first and second steps, or the subsequent fixing step, a hologram recording material excellent in nondestructive reproduction and storage stability can be provided.
For example, when a 532 nm laser is used again to irradiate the recorded hologram recording material, the recorded information, images, etc. can be reproduced or function as a desired optical material.

  Preferable examples of the latent image color development-chromogen sensitized polymerization reaction include those described in Japanese Patent Application No. 2004-238392.

4) Interference fringe recording by change in orientation of compound having intrinsic birefringence Preferably, the orientation change of the compound having intrinsic birefringence is caused by hologram exposure and is fixed as it is by a chemical reaction so that it cannot be rewritten. An interference fringe recording is performed as refractive index modulation. As the compound having an intrinsic birefringence, a liquid crystal compound is preferable, a low molecular liquid crystal compound is more preferable, and a low molecular liquid crystal compound having a polymerizable group is further preferable. The low molecular liquid crystalline compound having a polymerizable group is preferably a nematic liquid crystalline compound, a smectic liquid crystalline compound, a discotic nematic liquid crystalline compound, a discotic liquid crystalline compound, or a cholesteric liquid crystalline compound, and has a nematic liquid crystalline property. Or it is more preferable that it is smectic liquid crystallinity.
Further, in the hologram recording material in the interference fringe recording method by the orientation change of the compound having an intrinsic birefringence, it is preferable to have at least a low molecular liquid crystalline compound having a polymerizable group, a photoreactive compound, a polymerization initiator, It is also preferable to have a sensitizing dye, a binder polymer and the like. Preferred examples of the polymerization initiator, sensitizing dye, binder polymer and the like are as described above.
The photoreactive compound is preferably a photoisomerization compound, more preferably an azobenzene compound, a stilbene compound, a spiropyran compound, a spirooxazine compound, a diarylethene compound, a fulgide compound, a fulgimide compound, or cinnamic acid. Compound, a coumarin compound, or a chalcone compound, most preferably an azobenzene compound.
The photoreactive compound may be a low molecular compound or a polymer compound. When the photoreactive compound is a polymer compound, it is preferably a polymer compound in which a photoreactive site is pendant.
As a specific example of the interference fringe recording method and material based on the orientation change of the compound having an intrinsic birefringence, an example described in Japanese Patent Application No. 2003-327594 is preferable.

5) Dye-decoloring reaction Preferably, it has at least one or more decolorable dyes, and the decoloring dyes form interference fringes by refractive index modulation using decoloring by hologram exposure. And a hologram recording method.

  In the present invention, the decolorizable dye has absorption in the ultraviolet, visible and infrared regions of 200 to 2000 nm, and λmax is shortened directly or indirectly by light irradiation, and the molar absorption of absorption. The generic name of the dye that causes any decrease in the coefficient is shown, and more preferably, the dye causes both. Moreover, it is more preferable that the decoloring reaction occurs in a wavelength region of 200 to 1000 nm, and it is further preferable that the decoloring reaction occurs in a wavelength region of 300 to 900 nm.

As a preferable combination,
(A) The decolorizable dye is a sensitizing dye that absorbs at the hologram exposure wavelength, and forms interference fringes by refractive index modulation using absorbing the light during the hologram exposure and decoloring itself as a result. And a hologram recording method.
(B) A sensitizing dye having absorption at least at the hologram exposure wavelength and a decolorizable dye having a molar extinction coefficient of 1000 or less, preferably 100 or less, at the hologram reproduction light wavelength. A hologram recording method comprising forming interference fringes by refractive index modulation using absorption and decolorization of a decolorizable dye by electron transfer using the excitation energy or energy transfer.
The method (B) is more preferable.

Furthermore, it has a decoloring agent precursor that is different from the decoloring dye and sensitizing dye, and after the sensitizing dye or decoloring dye generates an excited state by hologram exposure, energy transfer with the decoloring agent precursor Alternatively, the decoloring agent is generated from the decoloring agent precursor by electron transfer, and the decoloring agent forms an interference fringe by refractive index modulation using decoloring of the decoloring dye. A hologram recording method is also preferable. In that case, the decoloring agent is preferably any one of a radical, an acid, a base, a nucleophile, an electrophile, and a singlet oxygen. Therefore, the decoloring agent precursor is a radical generator, an acid generator, a base. It is preferably any of a generator, a nucleophile generator, an electrophile generator, and triplet oxygen. The decoloring precursor is more preferably any of a radical generator, an acid generator and a base generator.

  In any case, it is more preferable to further include a binder polymer, and examples of the binder polymer include the above-described binder polymers and binder polymers particularly preferable in the present invention described below.

Next, in the “dye decoloring reaction method”, a decolorizable dye for forming a difference in refractive index between the interference fringe bright part and the dark part will be described in detail.
In the above-described method (A), since both the sensitizing dye and the decoloring dye are used, a preferred example of the decoloring dye includes the above-described examples of the sensitizing dye. It is preferable that λmax of the sensitizing dye / decolorizable dye is between the hologram recording light wavelength and the wavelength region shorter by 100 nm from the hologram recording light wavelength.

  On the other hand, in the above-described method (B), a decolorizable dye is used separately from the sensitizing dye. In that case, the decolorizable dye preferably has a molar extinction coefficient of the hologram recording light wavelength of 1000 or less, more preferably 100 or less, and most preferably 0. The λmax of the decolorizable dye is preferably between the hologram recording light wavelength and a wavelength region shorter by 200 nm from the hologram recording light wavelength.

  In the method (B), the decolorizable dye is preferably a cyanine dye, squarylium cyanine dye, styryl dye, pyrylium dye, merocyanine dye, benzylidene dye, oxonol dye, coumarin dye, pyran dye, xanthene dye, thiol. Xanthene dye, phenothiazine dye, phenoxazine dye, phenazine dye, phthalocyanine dye, azaporphyrin dye, porphyrin dye, condensed ring aromatic dye, perylene dye, azomethine dye, azo dye, anthraquinone dye, metal complex dye More preferably, any of a cyanine dye, a styryl dye, a merocyanine dye, a benzylidene dye, an oxonol dye, a coumarin dye, a xanthene dye, an azomethine dye, an azo dye, and a metal complex dye.

In particular, when the decolorizer is an acid, the decolorizable dye is preferably a dissociated benzylidene dye, a dissociated oxonol dye, a dissociable xanthene dye, a dissociated form of a dissociable azo dye, a dissociable benzylidene dye, More preferred is a dissociated oxonol dye or dissociated azo dye. Here, the dissociation type dye has an active hydrogen having a pKa in the range of about 2 to 14 such as —OH group, —SH group, —COOH group, —NHSO ₂ R group, —CONHSO ₂ R group, etc. Is a general term for dyes whose absorption becomes longer or higher ε due to dissociation. Therefore, if the dissociated dye is treated with a base in advance to obtain a dissociated dye, a dye having a long wavelength or a high ε can be prepared in advance, and it can be changed to a non-dissociated form by photoacid generation and decolored (short wavelength). Or low ε).

  In particular, when the decolorizer is a base, if an acid color-developing dye color former such as triphenylmethane dye, xanthene dye, or fluorane dye previously treated with an acid as a color former is used as the decoloring dye, It becomes possible to change to an aprotic adduct by generating a base and decolorize (shorter wavelength or lower ε).

  Specific examples of the decolorizable dye of the present invention are given below, but the present invention is not limited thereto.

Further, as the decolorizable dye of the present invention, the following examples of decolorizable dyes that can be decolored as a result of bond breakage due to electron transfer from the excited state of the sensitizing dye generated by hologram exposure are also preferable. Can be mentioned.
Although these decolorizable dyes are originally cyanine dyes, they are changed to cyanine bases (leucocyanine dyes) due to bond breakage due to electron transfer, and decoloration or shortening of absorption occurs.

  When the decolorizer precursor is an acid generator, preferred examples include the above-described cationic polymerization initiators. In the case of a radical generator, preferred examples include the aforementioned radical polymerization initiators. In the case of a base generator, preferred examples include the aforementioned anionic polymerization initiators.

  Preferable examples of the dye decoloring reaction include those described in Japanese Patent Application No. 2004-88790.

6) Residual decolorizable dye latent image-latent image sensitized polymerization reaction Preferably, a sensitizing dye having absorption at the hologram exposure wavelength absorbs light during hologram exposure to generate an excited state, and then uses the excitation energy. A first step of erasing a decolorizable dye having a molar extinction coefficient of a hologram reproduction light wavelength of 1000 or less, preferably 100 or less, and most preferably 0, and using a remaining decolorizable dye as a latent image. And a second step of recording the interference fringes as refractive index modulation by irradiating the residual decolorizable dye latent image with light having a wavelength different from that of the hologram exposure. This method is excellent in high-speed recording, suitability for multiple recording, storability after recording, and the like.
Further, after the sensitizing dye having absorption at the hologram exposure wavelength absorbs light at the time of hologram exposure to generate an excited state, the decolorizer is transferred by energy transfer or electron transfer with the decolorizer precursor described in 5). A decoloring agent is generated from the precursor, and the decoloring agent decolorizes the decolorizable dye, whereby a first step of forming a residual decolorable dye that has not been decolored as a latent image, and the residual decoloration By irradiating the chromatic dye latent image with light having a wavelength different from that of hologram exposure, the polymerization initiator is activated by energy transfer or electron transfer to cause polymerization, and the interference fringes are recorded as refractive index modulation. A hologram recording method characterized by having a step is also preferable.

Further, as a compound group capable of such a hologram recording method, at least,
1) a sensitizing dye that absorbs light and generates an excited state by hologram exposure in the first step;
2) Hologram reproduction light that can be decolored as a result of direct electron transfer from the excited state of the sensitizing dye in the first step or as a result of generating a decolorant by electron transfer to the decolorizer precursor. A decolorizable dye having a molar extinction coefficient of 1000 or less,
3) A decolorizer precursor of a polymerization initiator (possibly 2) capable of initiating polymerization of the polymerizable compound by electron transfer or energy transfer from the remaining decolorizable dye excited state in the second step. )
4) a polymerizable compound,
5) binder,
It is preferable to contain. In the case of energy transfer or electron transfer to the decolorizer precursor in 2), 6) the decolorizer is generated by electron transfer or energy transfer from the sensitizing dye excited state in the first step. It is also preferred to include a decolorant precursor that can be used.

Preferred examples of the sensitizing dye are the same as those described in 1) Color development reaction. Preferred examples of the polymerization initiator, the polymerizable compound and the binder are the same as those described in the section of 3) Latent image color development-coloring body sensitization polymerization reaction. Further, binder polymers particularly preferable in the present invention described below are also included.
Preferred examples of the decolorizable dye and decolorant precursor are the same as those described in 5) Decolorization reaction.
In the wavelength range of the light irradiated in the second step, the molar absorption coefficient of linear absorption of the sensitizing dye is more preferably 1000 or less, and further preferably 500 or less.
Moreover, it is preferable that the molar extinction coefficient of the decolorizable dye is 1000 or more in the wavelength range of the light irradiated in the second step.

Here, in the “residual decoloring dye latent image-latent image sensitization polymerization method” of the present invention, it is also preferable that the decoloring agent precursor and the polymerization initiator are partially or entirely the same and serve both functions.
When a decolorizable dye is added separately from the sensitizing dye and the decolorizer precursor and the polymerization initiator are different (for example, the decolorizer precursor is an acid generator or a base generator, the polymerization initiator is a radical Polymerization initiator or decolorizer precursor is radical generator or nucleophile generator, polymerization initiator is acid generator or base generator), sensitizing dye is electron only to decolorizer precursor It is preferable that transfer sensitization is possible and the polymerization initiator is capable of electron transfer sensitization only with a decolorizable dye.

  In the hologram recording method of the present invention and the hologram recording material capable of such recording, either by the first step, the second step, or the subsequent fixing step by light irradiation, heat application, or both. Decomposing and fixing the sensitizing dye is preferable in terms of storage stability and non-destructive regeneration, and further, a fixing step by the first step, the second step, or subsequent light irradiation, heat application, or both. It is more possible to decompose and fix the decolorizable dye remaining in either the second step or the fixing step by the subsequent light irradiation, heat application, or both. preferable.

The concept of “residual decoloring dye latent image-latent image sensitized polymerization reaction method” will be described below.
For example, a hologram recording material is irradiated with a 532 nm YAG / SHG laser and absorbed by a sensitizing dye to generate an excited state. The decoloring agent is generated by causing energy transfer or electron transfer from the excited state of the sensitizing dye to the decoloring agent precursor to decolorize the decoloring dye. As a result, it is possible to form a latent image with the remaining decolorizable dye (first step). Next, light in the wavelength region of 350 to 420 nm is irradiated to cause absorption of the residual decolorizable dye latent image, and the polymerization initiator is activated by electron transfer or energy transfer to initiate polymerization. For example, when the polymerizable compound has a refractive index lower than that of the binder, the refractive index is lowered because the polymerizable compound is collected at the portion where the polymerization occurs (second step). In the portion where the interference bright portion is formed in the first step, there is little residual decolorizable dye that becomes a latent image, so that polymerization does not occur so much in the second step and the abundance ratio of the binder becomes high. A large refractive index modulation can be formed in the interference dark part, and recording can be performed as interference fringes. If the sensitizing dye and the remaining decolorizable dye can be decomposed and decolored by the first and second steps or further fixing step, a hologram recording material excellent in nondestructive reproduction and storage stability can be provided. .
For example, when a 532 nm laser is used again to irradiate the recorded hologram recording material, the recorded information, images, etc. can be reproduced or function as a desired optical material.

  Preferred examples of the residual decolorizable dye latent image-latent image sensitization polymerization reaction include the examples described in Japanese Patent Application No. 2004-88790.

  In addition to the sensitizing dye, the interference fringe recording component, the polymerization initiator, the polymerizable compound, the binder, the decoloring dye, the decoloring agent precursor, etc. In addition, additives such as an electron donating compound, an electron accepting compound, a chain transfer agent, a crosslinking agent, a heat stabilizer, a plasticizer, and a solvent can be used.

Electron-donating compounds have the ability to reduce radical cations of sensitizing dyes, color formers or decolorizable dyes, and electron-accepting compounds have the ability to oxidize radical anions of sensitizing dyes, color formers or decolorable dyes. Both have a function of regenerating a sensitizing dye, a color former or a decolorizable dye. Specifically, for example, an example described in Japanese Patent Application No. 2004-238077 is given as a preferred example.
In particular, the electron donating compound is useful for high sensitivity because it can quickly regenerate the sensitizing dye, the color former or the decolorable dye radical cation after the electron transfer to the dye precursor group. As the electron donating compound, those having an oxidation potential lower than the oxidation potential of the sensitizing dye, color former or decolorizable dye are preferable. Preferred specific examples of the electron donating compound are listed below, but the present invention is not limited thereto.

  Especially as an electron-donating compound, a phenothiazine type compound (for example, 10-methylphenothiazine, 10- (4′-methoxyphenyl) phenothiazine), a triphenylamine type compound (for example, triphenylamine, tri (4′-methoxyphenyl) amine) , TPD compounds (such as TPD) are preferred, phenothiazine compounds are more preferred, and N-methylphenothiazine is most preferred.

The sensitizing dye, acid generator, base generator, dye precursor, decolorizable dye, decolorant precursor, electron donating compound, etc. of the present invention described above may be oligomers or polymers. It may be contained in the main chain or in the side chain, and may be a copolymer.
The polymer main chain may have any structure, and preferred examples include polyacrylates, polymethacrylates, polyethers such as polystyrene and polyethylene oxide, polyesters, polyamides, and the like.
In this case, the polymer or oligomer of the present invention has a repeating unit of 2 to 1,000,000, preferably 3 to 1,000,000, more preferably 5 to 500,000, and most preferably 100,000 to 100,000. It is as follows.
The molecular weight of the polymer or oligomer is preferably 500 or more and 10 million or less, more preferably 1000 or more and 5 million or less, further preferably 2000 or more and 1 million or less, and most preferably 3000 or more and 1 million or less. .

  Specific examples of the chain transfer agent, the crosslinking agent, the heat stabilizer, the plasticizer, the solvent, and the like include the examples described in Japanese Patent Application No. 2004-238392.

The chain transfer agent is preferably a thiol, such as 2-mercaptobenzoxazole, 2-mercaptobenzthiazole, 2-mercaptobenzimidazole, 4-methyl-4H-1,2,4-triazole-3-thiol, Examples include p-bromobenzenethiol, thiocyanuric acid, 1,4-bis (mercaptomethyl) benzene, p-toluenethiol and the like.
In particular, when the polymerization initiator is 2,4,5-triphenylimidazolyl dimer, it is preferable to use a chain transfer agent.

A heat stabilizer can be added to the hologram recording material of the present invention in order to improve storage stability during storage.
Useful heat stabilizers include hydroquinone, phenidone, p-methoxyphenol, alkyl and aryl substituted hydroquinones and quinones, catechol, t-butylcatechol, pyrogallol, 2-naphthol, 2,6-di-t-butyl-p. -Cresol, phenothiazine, chloranneal and the like.

  The plasticizer is used to change the adhesiveness, flexibility, hardness, and other mechanical properties of the hologram recording material. Examples of the plasticizer include triethylene glycol dicaprylate, triethylene glycol bis (2-ethylhexanoate), tetraethylene glycol diheptanoate, diethyl sebacate, dibutyl suberate, tris (2-ethylhexyl) phosphate, Examples include tricresyl phosphate, dibutyl phthalate, alcohols, and phenols.

  Next, a particularly preferable binder (thermosetting polymer) in the present invention will be described.

  The binder polymer preferably includes a reactive polymer and a cross-linking agent and forms a polymer matrix by a polymerization reaction (for example, a thermal reaction). More preferably, the reactive polymer is a polyol, the cross-linking agent is an NCO-terminated prepolymer (isocyanate), and an exothermic peak is generated within 12 minutes after mixing the polyol and the NCO-terminated prepolymer. . An optical recording medium made of a hologram recording material produced using the binder polymer has less product variation, no bubbles, optically flatness, and uniform thickness. As a result, the product has excellent optical properties. And the produced product has the desired dynamic range and sensitivity.

  In order to meet the requirements for its optical properties, care must be taken to fully degas all materials before activating the reaction with heat or catalyst. In addition, any impurities that generate gas as a by-product need to be removed, thereby preventing bubbles from forming in the final cured matrix system.

  Furthermore, in order to enable mass production of optical recording media, it is preferable to form the thermal crosslinking matrix system in a short time (preferably in 20 minutes or less).

  To make a high performance optical recording medium based on a two component urethane matrix system, for example, the polyol and all additives need to be substantially free of moisture. Once the isocyanate, the polyol containing the catalyst, and all other components are mixed, it is necessary to degas to remove any air introduced into the mixture during mixing. Since deaeration takes time, it is necessary to prevent the urethane reaction from occurring until all the bubbles are removed from the mixture of isocyanate and polyol.

  The polyol is selected from polytetramethylene glycol, polycaprolactone, polypropylene oxide diol and triol. Preferred polyols are polypropylene oxide triol and polytetramethylene ether diol having a molecular weight of 450 to 6000. The polyol preferably does not contain moisture. An additive such as a high-temperature vacuum distillation treatment or a water removing agent can be used to prevent water from remaining in the polyol before use.

  Additives include butylated hydroxytoluene (BHT), phenothiazine, hydroquinone, and methyl ether of hydroquine, and peroxide, phosphite, and hydroxyamine, and a defoamer to remove entrained bubbles or Deaerator is included.

  A tin catalyst can also be used. This includes dimethyl dilaurate tin, dibutyl dilacrate tin, stannous octoate, and the like.

  The binder polymer is formed by a process including a step of mixing a matrix precursor and a light refractive index modulation component and a step of curing the mixture in situ to form a matrix. The reaction for polymerizing the matrix precursor at the time of curing is a reaction independent of the photorefractive index modulation reaction of the photorefractive index modulation component, and it is desirable not to react the photorefractive index modulation component during the polymer matrix formation reaction. As a result of the independence between the polymer matrix and the optical refractive index modulation component, useful recording characteristics are imparted to an optical recording medium made of a hologram recording material. For example, it is possible to form a large modulation in the refractive index without increasing the optical refractive index modulation component.

As described above, the binder polymer can be obtained by mixing a matrix precursor and a light refractive index modulation component, and curing the precursor in situ to form a polymer matrix. In the matrix precursor and the light refractive index modulation component, the reaction of polymerizing the matrix precursor at the time of curing is a reaction independent of the light refractive index modulation reaction of the light refractive index modulation component. That is, the light refractive index modulation component is substantially inactive when the matrix is cured. Formation of the polymer matrix is considered complete when it exhibits a modulus of at least about 10 ⁵ Pa, generally from about 10 ⁵ Pa to about 10 ⁹ Pa, preferably from about 10 ⁶ Pa to about 10 ⁸ Pa.

  The at least one photorefractive index modulating component includes one or more components that are substantially absent from the polymer matrix, except for the functional group. Here, “substantially not present” means that the optical refractive index modulation component is present in the matrix in an amount of 20% or less of all the components in the recording material, that is, is not covalently bonded. The resulting hologram recording material exhibits a preferable refractive index difference because the polymer matrix is independent of the optical refractive index modulation component.

  A polymer matrix is a solid polymer formed in situ from a matrix precursor by a curing process (curing refers to the process of reacting a precursor to form a polymer matrix). The precursor can be one or more monomers, one or more oligomers, or a mixture of monomers and oligomers. Furthermore, one or more precursor functional groups may be contained in one precursor molecule or in a precursor molecule group. Precursor functional groups refer to one or more groups in the precursor molecule that serve as polymerization sites when the matrix is cured. In order to facilitate mixing with the photorefractive index modulating component, the precursor is preferably a liquid at a temperature range of about −50 ° C. to about 80 ° C. The matrix polymerization is preferably carried out at room temperature. The polymerization is preferably performed within 5 minutes. The glass transition temperature (Tg) of the holographic recording material is preferably low enough so that the optical refractive index modulation component undergoes sufficient diffusion and chemical reaction during the holographic recording process. In general, Tg preferably does not exceed 50 ° C. above the temperature at which holographic recording takes place, and for typical holographic recording, Tg is preferably between about 80 ° C. and about −130 ° C. (normal Measured by the method).

In the present invention, examples of the polymerization reaction used to form the polymer matrix include cationic epoxy polymerization reaction, cationic vinyl ether polymerization reaction, cationic alkenyl ether polymerization reaction, cationic allyl ether polymerization reaction, cationic ketene acetal polymerization reaction, epoxy amine Step polymerization reaction, epoxy mercaptan step polymerization reaction, unsaturated ester amine step polymerization reaction (by Michael addition), unsaturated ester mercaptan step polymerization reaction (by Michael addition), vinyl-silicon hydride step polymerization reaction (hydrosilylation), It is a polymerization reaction comprising an isocyanate-hydroxyl step polymerization reaction (urethane formation reaction), an isocyanate-amine step polymerization reaction (urea formation reaction), or a combination thereof. Among these, an isocyanate-hydroxyl step polymerization reaction, an isocyanate-amine step polymerization reaction, or a combination thereof is preferable.

Some of these reactions can be initiated or accelerated by using a suitable catalyst. For example, cationic epoxy polymerization can be rapidly carried out at room temperature by using a BF ₃ -based catalyst, other cationic polymerization proceeds in the presence of protons, and epoxy-mercaptan reaction and Michael addition are bases such as amines. Hydrosilylation proceeds rapidly in the presence of a transition metal catalyst such as platinum, and urethane and urea formation can proceed rapidly by using a tin catalyst. A photoactivated catalyst can also be used for matrix formation.

An example of the composition of the hologram recording material using the binder polymer is composed of the following components.
NCO-terminated prepolymer 20-50% by mass
Photorefractive index modulation component 1 to 15% by mass
Polyol 40-75% by mass
0.1 to 3% by mass of catalyst
Additive 0.001-0.5 mass%

  The NCO-terminated prepolymer is a byproduct of the reaction of diol and diisocyanate and can be selected from those having an NCO content of 10 to 25% by weight. The NCO content can be calculated based on the prepolymer, the unreacted diisocyanate, and the polyisocyanate added as necessary to improve the properties. Aromatic diisocyanate prepolymers are preferred. However, if the NCO-terminated prepolymer is based on an aliphatic diisocyanate, 5-100% by weight of the NCO content needs to be from an aromatic diisocyanate or an aliphatic polyisocyanate. Preferred aromatic diisocyanates are, but not limited to, diphenylmethane diisocyanate (MDI) and toluene diisocyanate (HDI). Preferred aliphatic isocyanates are hexamethylene diisocyanate (HDI) and its biurets, isocyanurates, uretidiones, and other derivatives.

Particularly preferred are the following two examples.
(1) NCO-terminated prepolymer formed by the reaction of biscyclohexylmethane diisocyanate, biscyclohexylmethane diisocyanate and polytetramethylene glycol, butylated hydroxytoluene, and / or a derivative of hexamethylene diisocyanate And the polyol contains a polypropylene oxide polyol and a polytetramethylene ether polyol, and an exothermic peak occurs within 12 minutes after mixing the polyol and the NCO-terminated prepolymer.
(2) the NCO-terminated prepolymer includes a material selected from diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and a derivative of hexamethylene diisocyanate, and the polyol includes a polyol of polypropylene oxide, and An exothermic peak occurs within 12 minutes after mixing with the NCO-terminated prepolymer.

When producing an optical recording medium using the binder polymer, for example, a mixture of a matrix precursor and a light refractive index modulation component is deposited between two plates using, for example, a gasket that holds the mixture. be able to. The plate is typically glass, but other materials that are transparent to the illuminating light used to record the data, for example, plastics such as polycarbonate or poly (methyl methacrylate) can also be used. A spacer for making the optical recording medium have a desired thickness can be disposed between the two plates. When the matrix is cured, stress is generated in the plate due to the shrinkage of the material, and the parallelism and / or spacing of the plate changes due to the stress, which adversely affects the optical properties of the medium. In order to eliminate such influence, it is effective to arrange the plate in a device provided with a support table, for example, a vacuum chuck. This allows adjustment in response to changes that change parallelism and / or spacing. In such an apparatus, it is also possible to monitor parallelism in real time using conventional interferometry, thereby making necessary adjustments during curing. The method is described, for example, in US patent application Ser. No. 08 / 867,563, and becomes a part of this specification by indicating the name of the document. The hologram recording material of the present invention can be supported by other methods. For example, it is contemplated that the matrix precursor / light index modulating component mixture may be placed in a substrate, for example, a hole in a nanoporous glass material such as Vycor glass, prior to curing of the matrix. In addition, conventional polymer processes such as closed mold or sheet extrusion are also included. A layered medium, i.e. a medium comprising a number of substrates, such as glass, with a layer of recording material between the substrates is also conceivable.

The amount of information recorded on the hologram recording material is proportional to the product of the refractive index difference Δn of the recording material and the thickness d of the recording material. (The refractive index difference Δn is conventionally known and is defined as the intensity of a sinusoidal change in the refractive index of a material on which a plane wave and a volume hologram are recorded. The refractive index is n (x) = n ₀ + Δn cos ( K _x ), where n (x) is the spatially varying refractive index, x is the position vector, K is the lattice wave vector, and n ₀ is the baseline refractive index of the medium P. Hariharan, Optical Holography: Principles,
See Techniques, and Applications, Cambridge University Press, Cambridge, 1991, at 44. The Δn of the material is usually calculated from the diffraction efficiency of a single volume hologram or multiple sets of volume holograms recorded on the medium. Δn is related to the medium before recording, but is observed by measurements performed after recording. The recording material of the present invention preferably has a thickness of 200 μm or more and Δn of 3 × 10 ⁻³ or more.

Next, another binder polymer particularly preferable in the present invention will be described.
Another preferable binder polymer is a phase-separated optical refractive index modulating component and the system thereof, and exhibits a Rayleigh ratio of about 7 × 10 ⁻³ or less at 90 ° light scattering at a wavelength effective for hologram formation. The light refractive index modulation component is formed by a reaction independent of the light refractive index modulation reaction. In particular, it is preferably made of a melamine-formaldehyde resin.

  The Rayleigh ratio (Rθ) is a conventionally known characteristic. When the medium is illuminated with unit intensity of unpolarized light, as described in Kerker, The Scattering of Light and Other Electromagnetic Radiation, Academic Press, 1969, 38, the unit quantity of azimuth θ per steradian is scattered. Defined as energy. This Rayleigh ratio is typically obtained by comparison with energy scattered by a reference material having a known Rayleigh ratio.

The elastic modulus of the binder polymer is preferably 10 ⁶ Pa or more. More preferably, the elastic modulus is 10 ⁶ Pa to about 10 ⁹ Pa, preferably 10 ⁷ Pa or more.

The hologram recording material of the present invention using the binder polymer is produced by mixing a light refractive index modulation component and a polymer matrix precursor and curing them. The curing reaction of the binder polymer is preferably performed by a reaction independent of the light refractive index modulation reaction of the light refractive index modulation component. Also, the polymer matrix and the photorefractive index modulating component are (a) the matrix precursor and photorefractive index modulating component are substantially soluble, ie miscible, but (b) as the matrix precursor polymerizes during curing. The resulting polymer and photorefractive index modulating component are selected to phase separate. This treatment can provide low light scattering and enables effective holography.

  The polymer matrix preferably exhibits a three-dimensional cross-linked structure to provide the desired strength. In particular, the cross-linked structure suppresses bulk shrinkage of the hologram recording material.

  Examples of polymerization reactions employed to form the polymer matrix include cationic epoxy polymerization, cationic vinyl ether polymerization, epoxy-amine step polymerization, epoxy-mercaptan step polymerization, and unsaturated (via Michael addition). Includes ester-mercaptan step polymerization, vinyl-silicon hydride step polymerization (hydrosilylation), isocyanate-hydroxyl step polymerization (urethane composition) and isocyanate-amine step polymerization (urea composition). Some of these reactions are functionalized or promoted with a suitable catalyst.

In order to provide phase separation properties, the photorefractive index modulating component and the matrix precursor (and the resulting polymer) are selected based on the matrix and the photorefractive index modulating component. Guidelines known to those skilled in the art are given, for example, in the polymer-scattered liquid crystal (PDLC) literature. For PDLC papers, see p. Drzaic, Liquid Crystal Dispersions, in Series on Liquid Crystals, Vol. 1, World Scientific (1995); W. Doane, “Polymer Dispersed Liquid Crystal Displays”, in Liquid Crystals-Applications
and Uses, Vol. 1,361-395, World Scientific
(1990). These disclosures are hereby incorporated by reference. The requirements for achieving the dispersion of the liquid crystal in the polymer matrix by polymer phase separation are essentially the same as the requirements for obtaining a clear region of the optical refractive index modulation component in the polymer matrix according to the invention. Phase separation induced by polymerization of oligomers in the original position is Drzaic, supra, at pages 31-47 and 75-92, this latter part discusses the associated dynamic requirements, and Doane, supra , At page 364. As shown in the reference, the final size of the distinct region of the refractive index modulation component includes the rate of region formation, the growth of the region by diffusion, and the mechanism by which the polymer matrix is confined in the entire structure. It will depend on many factors. For example, rapid polymerization tends to make the region smaller due to the early formation of the region and the rapid increase in the hardness of the matrix phase. Furthermore, Doane describes the effects of phase separation and refractive index contrast due to light scattering on pages 378-383.

For example, organic aerogels are described in US Pat. No. 5,081,163 to Pekala, G. Ruben and R.M. Pekala, “High Resolution TEM of Organic Aerogels and Organic Aerogels”, Mat. Res. Soc. Symp. Proc. , Vol. 180,785 (1990), L.L. Hrubesh and R.M. Pekala, “Thermal Properties of organic and organic aerogels,” J. Am. Mater. Res. , Vol. 9, no. 3,731 (1994) and R.A. Pekala et al. "A Company of Mechanical Properties and Scaling Law Relations for Silica Aerogels and Ther Organic Counterparts," Mat. Res.
Soc. Symp. Proc. , Vol. 207, 197 (1991). These disclosures are hereby incorporated by reference. These organic aerogels serve as the polymer matrix of the present invention and aid in phase separation due to the ability to form a porous matrix structure. For example, as described in US Pat. No. 5,081,163, column 6, lines 41-59, the fabrication of the airgel includes a solvent-filled hole, followed by removal of the solvent and airgel. The formation of a matrix containing the air-filled pore characteristics of However, in the present invention, it is desirable to hold the optical refractive index modulation component in these holes. The standard method of airgel fabrication with phase separation guidelines found in PDLC technology is effective in providing such a structure. The formation of such an organic airgel matrix containing a region of photorefractive index modulation component is shown in the following example. Airgel matrix structure by providing a photorefractive index modulating component that polymerizes by a mechanism independent of the matrix precursor and selecting the matrix precursor and the photorefractive index modulating component to phase separate based on the matrix polymerisation Interference with the formation process is reduced. Thereby, a structure desirable for the hologram recording material (that is, a clear region of the optical refractive index modulation component) can be obtained.

  In addition to dynamic requirements, variables such as concentration, molecular mass and curing conditions also have a significant effect on phase separation, and thus these variables are adjusted to provide the desired results. The refractive index contrast between the matrix and the optical refractive index modulation component is also a requirement when selecting a material to improve the holographic characteristics. The index contrast and the specific wavelength used also affect the Rayleigh ratio.

Since the binder polymer obtained as described above is phase-separated from the light refractive index modulation component, there is a clear region dominantly containing the light refractive index modulation component, and a wavelength of 90 used for hologram formation is present. The light scattering Rayleigh ratio (R ₉₀ °) is about 7 × 10 ⁻³ or less as described above. In general, a well-defined region of the optical refractive index modulation component having a maximum dimension of about 50 nm or less is suitable to achieve this low light scattering. Preferably, at least a portion of the distinct region of the refractive index modulation component is coupled to at least one other region so that the refractive index modulation component is transmitted to one region during hologram formation. Can be diffused more easily to the other region. It was observed that the rate of flood cure indicated that there was little monomer in the matrix, suggesting easy diffusion between regions. However, region size, region interconnection, and specific levels of light scattering are secondary to achieve effective holographic properties. Thus, region size and interconnection, and light scattering tend to vary based on the matrix and light index modulation components.

The hologram recording material of the present invention may be prepared by a usual method.
For example, as a method for forming a hologram recording material of the present invention, the binder and each component may be dissolved in a solvent and applied using a spin coater or a bar coater.
In that case, preferably as a solvent, for example, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, acetone, cyclohexanone, ester solvents such as ethyl acetate, butyl acetate, ethylene glycol diacetate, ethyl lactate, cellosolve acetate, cyclohexane, toluene, Hydrocarbon solvents such as xylene, ether solvents such as tetrahydrofuran, dioxane, diethyl ether, cellosolv solvents such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, dimethyl cellosolve, methanol, ethanol, n-propanol, 2-propanol, n- Alcohol solvents such as butanol and diacetone alcohol, fluorine solvents such as 2,2,3,3-tetrafluoropropanol, dichloromethane, chloroform , 1,2-halogenated hydrocarbon solvents such as dichloroethane, N, amide solvents such as N- dimethylformamide, acetonitrile, and nitrile-based solvents such as propionitrile.

The hologram recording material of the present invention can be applied directly on the substrate by using a spin coater, roll coater or bar coater, or can be cast as a film and laminated on the substrate by a usual method. It can be a hologram recording material.
Here, “substrate” means any natural or synthetic support, preferably one that can exist in the form of a flexible or rigid film, sheet or plate.
The substrate is preferably polyethylene terephthalate, resin-undercoated polyethylene terephthalate, polyethylene terephthalate treated with flame or electrostatic discharge, cellulose acetate, polycarbonate, polymethyl methacrylate, polyester, polyvinyl alcohol, glass or the like.
The solvent used can be removed by evaporation during drying. Heating or reduced pressure may be used for evaporation removal.

The hologram recording material of the present invention may be formed by melting a binder containing each component at a temperature equal to or higher than the glass transition temperature or the melting point of the binder and then subjecting it to melt extrusion or injection molding. At that time, a reactive cross-linking binder may be used as the binder, and the film may be cured by cross-linking after extrusion or molding to increase the film strength. In that case, radical polymerization reaction, cationic polymerization reaction, condensation polymerization reaction, addition polymerization reaction and the like can be used for the crosslinking reaction. In addition, methods described in JP-A Nos. 2000-250382 and 2000-172154 can be preferably used.
In addition, a method in which each component is dissolved in a monomer solution forming a binder and then the monomer is thermally polymerized or photopolymerized to form a polymer, which is preferably used as a binder. As a polymerization method at that time, a radical polymerization reaction, a cationic polymerization reaction, a condensation polymerization reaction, an addition polymerization reaction, or the like can be used.

  Furthermore, a protective layer for blocking oxygen may be formed on the hologram recording material. The protective layer is made of a plastic film or plate such as polyolefin such as polypropylene or polyethylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyethylene terephthalate or cellophane film by electrostatic adhesion or lamination using an extruder. Alternatively, the polymer solution may be applied. Further, a glass plate may be bonded. Further, an adhesive or a liquid substance may be present between the protective layer and the photosensitive film and / or between the base material and the photosensitive film in order to improve airtightness.

When the hologram recording material of the present invention is used for holographic optical memory, it is more preferable that the hologram recording material does not shrink before and after hologram recording from the viewpoint of improving the S / N ratio during signal reproduction.
Therefore, for example, an expansion agent described in JP-A-2000-86914 is used for the hologram recording material of the present invention, or a shrink-resistant binder described in JP-A-2000-250382, 2000-172154, and JP-A-11-344917 is used. It is also preferable to use it.
In addition, it is also preferable to adjust the interference fringe interval by using a diffusing element described in JP-A-3-46687, 5-204288, JP-A-9-506441 and the like.

In conventional ordinary photopolymers such as Patent Documents 1 to 3 and 5 to 8, if multiple recording is performed, the latter half of the multiple recording is recorded at a place where the polymerization has progressed considerably. Thus, even when recording the same signal, an exposure time is required (sensitivity is lowered), which is a serious problem in system design. That is, the range in which the refractive index modulation amount increases linearly with respect to the exposure amount is very narrow.
In contrast, the recording methods of 1) color development reaction, 2) latent image color development-colored body self-sensitized amplification color development reaction, and 5) dye decolorization reaction of the present invention are methods that do not involve polymerization in interference fringe recording, 3) Latent image color development-colored body sensitized polymerization reaction, 6) Residual decoloring dye latent image-recording method using latent image sensitized polymerization reaction is also almost complete during the hologram exposure (first step). This is a method of performing refractive index modulation by polymerization in a lump in the entire surface exposure in the second step without being accompanied. Therefore, many multiplex recordings are possible in any of the methods 1) to 3), 5) and 6), and the exposure amount during multiplex recording remains constant throughout the multiplex recording. Since multiple recording can be performed while the refractive index modulation amount increases linearly with respect to the exposure amount, a wide dynamic range can be obtained. As described above, the recording methods 1) to 3), 5), and 6) of the present invention using the coloring method, the decoloring method, or the latent image amplification method are very advantageous in view of the above-mentioned multi-recording suitability.
This is preferable in terms of increasing the density (capacity), simplifying the recording system, improving the S / N ratio, and the like.

  As described above, the hologram recording material of the present invention is a completely new recording method that can solve both of the above-mentioned problems and can achieve both high sensitivity, good storage stability, dry processing, and multiple recording characteristics (high recording density). In particular, it is preferably used for an optical recording medium (holographic optical memory).

  Further, the hologram recording material of the present invention is disclosed in JP-T-2005-500581, JP-A-2005-501285, JP-A-3393064, JP-A-2003-85768, JP-A-2004-265472, JP-A-2004-265472. It can be used for a recording medium described in JP 2004-126040 A. Further, the hologram recording material of the present invention is disclosed in JP-A Nos. 2004-272268, 2004-177958, 2003-43904, 3451663, 2004-335044, and 2004. JP-A No. 361928, JP-A No. 2004-171611, JP-A No. 2003-228849, JP-A No. 2002-83431, JP-A No. 2002-123948, JP-A No. 2004-30734, and JP-A No. 2004-362750. In Japanese Patent No. 3430012, Japanese Patent Laid-Open No. 2003-178457, Japanese Patent Laid-Open No. 2003-178458, Japanese Patent Laid-Open No. 2003-178462, Japanese Patent Laid-Open No. 2003-178484, Japanese Patent Laid-Open No. 2003-151143, etc. Hologram using the recording / reproducing apparatus described It can be recorded and reproduced.

  In addition to the optical recording medium, the hologram recording material of the present invention includes a three-dimensional display hologram, a holographic optical element (HOE, for example, a head-up display (HUD) mounted on an automobile, a pickup lens for an optical disk, a head mount. Displays, color filters for liquid crystals, reflective liquid crystal reflectors, lenses, diffraction gratings, interference filters, optical fiber couplers, optical polarizers for facsimiles, architectural window glass), covers for books, magazines, displays such as POPs, It can be preferably used for credit cards, banknotes, packaging and the like for security purposes for preventing gifts and counterfeiting.

EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not restrict | limited to the following example.
Example 1
[Hologram recording method by coloring method]
A Posiratio manufactured by Liquid Control was used, and its tank A was Baytech WE-180 (available from Bayer AG, which is an NCO-terminated prepolymer based on biscyclohexylmethane diisocyanate, biscyclohexylmethane diisocyanate and polytetramethylene glycol. 200 g of a 50/50 blend with a polymer), 200 g of Mondur ML (which is liquid diphenylmethane diisocyanate available from Bayer), a photorefractive index modulating component (described in the table below), butylated hydroxytoluene (BHT) 254 mg) was added and mixed well to degas to a uniform solution. In a tank B, 807 g of polypropylene oxide triol having a molecular weight of 1000, 310 μl of t-butyl peroxide and 10.1 g of dibutyl laurate tin were mixed well and degassed as a uniform solution. Next, the contents of tanks A and B were mixed to obtain compositions 101-110.
The hologram recording material compositions 101 to 110 were applied to a glass substrate with a blade so as to have a thickness of about 200 μm (overcoat if necessary) to form a photosensitive layer, and then polymerized at room temperature for 1 day. . Furthermore, hologram recording materials 101 to 110 were produced by covering the photosensitive layer with a TAC film.
The hologram recording material in the hologram recording materials 101 to 110 was exposed and recorded using a YAG laser double wave (532 nm, output 2 W) as a light source by the two-beam optical system for transmission hologram recording shown in FIG. The angle between the object beam and the reference beam is 30 degrees. The beam has a diameter of 0.6 cm and an intensity of 8 mW / cm ² , and the holographic exposure time varies from 0.1 to 400 seconds (irradiation energy ranges from 0.8 to 3200 mJ / cm ² ). And exposed. While exposing the hologram, a He—Ne laser beam of 632 nm was passed through the center of the exposure region at a black angle, and the ratio of the diffracted light to the transmitted light (relative diffraction efficiency) was measured in real time. In addition, since there is no absorption of a sensitizing dye at 632 nm, the He—Ne laser does not expose the hologram recording material. In FIG. 1, 10 is a YAG laser, 12 is a laser beam, 14 is a mirror, 20 is a beam splitter, 22 is a beam segment, 24 is a mirror, 26 is a spatial filter, 40 is a beam expander, and 30 is a hologram recording material. , 28 is a sample, 32 is a He—Ne laser beam, 34 is a He—Ne laser, 36 is a detector, and 38 is a rotary stage.
Further, the multiplicity M / # / 200 μm of the hologram recording material was measured. M / # is determined by the difference in refractive index and the thickness of the material, and a typical value is 1.5 or more. In this embodiment, M / # is converted to a material thickness of 200 μm. M / # is defined as the dynamic range of the recording material. M / # can be measured by multiplexing a series of holograms with exposure times set to consume all the optical refractive index modulation components in the material. M / # is defined as the sum of the square roots of the diffraction efficiencies of all multiplexed holograms.
Furthermore, the heat generation start, heat generation peak, and shrinkage of the hologram recording material were examined.
Exothermic start, i.e., the temperature of the material dispensed on the pan began to rise and the reaction started, measured by a thermocouple or thermometer inserted in the material dispensed on the pan . The time required for the temperature to rise from 24 ° C. to 30 ° C. was measured. The exothermic peak was recorded by monitoring the time at which the thermocouple or thermometer temperature peaked. Shrinkage (firstly the material thickness changes) is determined by measuring the Bragg detuning (reading angle shift) of the angle multiplexed hologram. The qualitative relationship between material physical shrinkage and Bragg detuning is described in detail in the above-mentioned literature. That is, Applied Physics Letters, Volume 73, Number 10, p. 1337-1339, 7 September 1998.
As a comparative example, a photopolymer hologram recording material of Example 1 (Comparative Example 1 below) of JP-T-2004-537620 was prepared.
The results are shown in Table 2.

From Table 2, examples such as those described in Japanese Patent Application Publication No. 2004-537620 are numerical values with high diffraction efficiency but insufficient M / # and shrinkage. On the other hand, since the hologram recording materials 101 to 110 of the present invention perform hologram recording by refractive index modulation using color development reaction without using mass transfer and polymerization, it is a completely different recording method from known hologram recording materials. It can be seen that both a high diffraction efficiency and an extremely small shrinkage rate of 0.01% or less can be achieved, and the multiplicity M / # is also high, which is particularly suitable for holographic memory applications.

Furthermore, the hologram recording material of the present invention increases Δn (calculated based on Kugelnick's formula from refractive index modulation amount, diffraction efficiency and film thickness in interference fringes) almost linearly according to the exposure amount (mJ / cm ² ). However, this is advantageous for multiple recording.

  Actually, using the hologram recording material of the present invention, the multiplex hologram recording was performed 10 times in the same place by changing the angle of the reference light by 2 degrees with the light amount of 1/10 of the exposure amount giving the maximum diffraction efficiency. After that, it was confirmed that each object light can be reproduced by changing the angle of the reproduction light by 2 degrees and irradiating. That is, it can be seen that the hologram recording material of the present invention is capable of multiple recording with the same exposure amount and has multiple recording suitability. As described above, since the hologram recording material of the present invention can perform multiple multiplex recording, high-density (capacity) recording is possible.

  On the other hand, known photopolymer type hologram recording materials such as JP-T-2004-537620 perform the same recording because the polymerization of the photopolymer proceeds and the movement of the monomer necessary for recording is delayed in the latter stage of multiple recording. In this case, it was found that a larger amount of irradiation light was required than in the initial stage, which proved to be a problem in improving the multiplicity, that is, the recording density.

In samples 101 to 110, the sensitizing dyes were S-1, S-4, S-8, S-10, S-11, S-19, S-23, S-31, S-33, S. -34, S-43, S-45, S-46, S-50, S-58, S-67, S-73, S-74, S-77, S-80, S-91, S-94 , S-95, S-96, the same effect was obtained.
Further, in Samples 101 to 107, the acid generator of the interference fringe recording component is I-3, I-4, I-6, I-7, I-8, I-9, I-10, 4- (octylphenyl). ) Phenyliodonium hexafluoroantimonate, tris (4-methylphenyl) sulfonium tetra (pentafluorophenyl) borate, triphenylsulfonium perfluoropentanoate, bis (1- (4-diphenylsulfonium) phenyl sulfide ditriflate, dimethylphena Even if it is changed to silsulfonium perfluorobutane sulfonate, benzoin tosylate, I-22, or I-23, the acid coloring type dye precursor of the interference fringe recording component in samples 101 to 107 is L-1, L-3. , LC-1, LC-4, LC-9, LC-11, LC-12, LC-13 Effect was obtained.
Even if the base generator of the interference fringe recording component in the sample 108 is changed to PB-3, PB-4, PB-5, PB-6, PB-7, PB-8, PB-9, the sample At 108, the base color-forming dye precursor (dissociable dye non-dissociated substance) is converted to DD-1, DD-13, DD-15, DD-17, DD-22, DD-30, DD-31, DD-32, The same effect was obtained even when changed to DD-34, DD-35, DD-36, DD-37, DD-38.
Further, in the samples 109 and 110, the interference fringe recording components are E-5, E-9, E-10, E-11, E-12, E-13, E-14, E-15, E-16, E The same effect was obtained even when changed to -18, E-20, E-25, E-26, E-27, E-28, E-29, and E-30.
Further, even if the electron donor is changed to A-2, A-3, A-4, A-5, A-6, A-9, A-10, or A-11 in the samples 103 and 106 to 109, Similar effects were obtained.
In Samples 101 to 110, the binder was changed to polymethyl methacrylate (Mw 996000, 350,000, 120,000), poly (methyl methacrylate-butyl acrylate copolymer (Mw 75000), polyvinyl acetal (Mw 83000), polycarbonate, cellulose acetate butyrate, etc. However, the same effect was obtained.
In Samples 101 to 110, Baytech WE-180, which is a component of the binder polymer, is Baytech MP-160 (available from Bayer, an NCO-terminated prepolymer based on diphenylmethane diisocyanate and polypropylene ether glycol. The same effect was obtained even when changed to). In addition, the isocyanate blend, which is a component of the binder polymer, was changed to Baytech WE-180 (180 g), Desmodur N3200 (available from Bayer, which is a biuret derivative of HDI) (120 g), and the polyol blend was changed to PMEG. The same effect was obtained even when the molecular weight was changed to 1000 (which is a polytetramethylene ether diol having a molecular weight of 1000) (300 g) and a molecular weight of 1500 polypropylene oxide triol (300 g).
Further, in Samples 101 to 110, the same effect was obtained even when the binder polymer was changed to a melamine formaldehyde resin (for example, poly (melamine-co-formaldehyde) methylated resin available from Aldrich Chemical Company)).

Example 2
[Latent image color development-hologram recording method by color-sensitized polymerization reaction method]
Hologram recording materials 201 to 204 were produced in the same manner as in Example 1 except that the components shown in Table 3 were used. % Represents mass%.

The hologram recording material was exposed and recorded using a YAG laser double wave (532 nm, output 2 W) as a light source by the two-beam optical system for transmission hologram recording shown in FIG. The angle between the object beam and the reference beam is 30 degrees. The beam has a diameter of 0.6 cm and an intensity of 8 mW / cm ² , and the holographic exposure time varies from 0.1 to 40 seconds (irradiation energy ranges from 0.8 to 320 mJ / cm ² ). (First step) A He-Ne laser beam of 632 nm is passed through the center of the exposure area at the black angle, and the ratio of the diffracted light to the transmitted light (relative diffraction efficiency) is measured in real time. (Diffraction efficiency η after the first step). In addition, since there is no absorption of a sensitizing dye at 632 nm, the He—Ne laser does not expose the hologram recording material.
Further, the entire surface was irradiated with light having a wavelength range of 370 to 410 nm (second step), and the diffraction efficiency was measured (diffraction efficiency η after the second step). Further, the amount of irradiation necessary to obtain the maximum diffraction efficiency only in the first step without using the second step is divided by the amount of irradiation necessary for the first step when the second step is used. Is the “amplification factor” and the above is summarized in Table 4.

  From Table 4, in the hologram recording material of the present invention, the amount of light irradiated to the first step can be reduced to 1/5 to 1/7 as compared with the case where the second step is not used. Since the second process is capable of batch exposure, the first process can be shortened, that is, increased by amplification of refractive index modulation recording by causing polymerization of the color former of the first process in the second process as a latent image. It turns out that sensitivity improvement is possible. Needless to say, it is impossible to increase the sensitivity by such amplification with known materials as described in JP-T-2004-537620. It can also be seen that M / # also shows a higher value than that of JP-T-2004-537620.

Furthermore, the hologram recording material of the present invention is substantially linear in accordance with the exposure amount (mJ / cm ² ) after the first step and after the second step, Δn (refractive index modulation amount, diffraction efficiency and film in interference fringes). This is advantageous in the case of multiple recording.

  Actually, using the hologram recording material of the present invention, 10 times of multiple hologram recording was performed at the same place by changing the angle of the reference light by 2 degrees with the light amount of 1/10 of the exposure amount in the first step. After performing (first step), the entire surface was irradiated with light having a wavelength range of 370 to 410 nm to perform recording amplification by polymerization (second step). The angle of the reproduction light was changed by 2 degrees and irradiated. By doing so, it was confirmed that each object light can be reproduced. That is, it can be seen that the hologram recording material of the present invention can perform multiple recording with the same exposure amount and has multiple recording suitability. That is, the holographic recording material of the present invention can perform many multiplex recordings and can perform high density (capacity) recording.

On the other hand, known photopolymer type hologram recording materials such as JP-T-2004-537620 perform the same recording in the latter stage of multiple recording because the polymerization of the photopolymer progresses and the movement of the monomer necessary for recording slows down. At this time, it was found that a larger amount of irradiation light was required than in the initial stage, which proved to be a problem in improving the multiplicity, that is, the recording density.
On the other hand, the hologram recording method of the present invention uses a color development reaction instead of polymerization for the hologram recording (first step) and uses it as a latent image. Are better.

In samples 201 to 204, the sensitizing dyes are S-1, S-4, S-8, S-10, S-11, S-19, S-23, S-31, S-33, S. -34, S-43, S-45, S-46, S-50, S-58, S-67, S-71, S-73, S-74, S-75, S-77, S-80 , S-81, S-88, S-91, S-94, S-95, S-96, the same effect was obtained.
Further, in the samples 201 and 202, the acid generator (also serving as cation or radical polymerization initiator) of the interference fringe recording component is I-3, I-4, I-6, I-7, I-8, I-9, I-10,4- (octylphenyl) phenyliodonium hexafluoroantimonate, tris (4-methylphenyl) sulfonium tetra (pentafluorophenyl) borate, triphenylsulfonium perfluoropentanoate, bis (1- (4-diphenyl) Even if it is changed to sulfonium) phenyl sulfide ditriflate or dimethylphenacylsulfonium perfluorobutane sulfonate, the acid coloring type dye precursor of the interference fringe recording component in samples 201 and 202 is L-1, L-3, LC-1. , LC-4, LC-9, LC-11, LC-12, LC-13 Obtained.
In Sample 203, the interference fringe recording component and polymerization initiator base generator (also anion polymerization initiator) were used as PB-3, PB-4, PB-5, PB-6, PB-7, and PB-8. , PB-9, the base color-forming dye precursor (dissociable dye non-dissociated substance) is changed to DD-1, DD-13, DD-15, DD-17, DD-22, DD in Sample 203. The same effect was obtained even if it was changed to -30, DD-31, DD-32, DD-34, DD-35, DD-36, DD-37, DD-38.
In Sample 204, the dye precursors are E-3, E-5, E-9, E-10, E-11, E-12, E-13, E-14, E-15, E-16, Even if it changes to E-18, E-20, E-25, E-26, E-27, E-28, E-29, E-30,
Even when the radical polymerization initiator was changed to I-1, I-11 to I-20 or the like in sample 204, the same effect was obtained.
In addition, it is the same even if the electron donor is changed to A-2, A-3, A-4, A-5, A-6, A-9, A-10, A-11 in Samples 201 to 204. The effect was obtained.
In the above case, the optimal wavelength was used for the light for performing the entire surface exposure in each system.
In Samples 201 to 204, Baytech WE-180, which is a component of the binder polymer, is Baytech MP-160 (available from Bayer, an NCO-terminated prepolymer based on diphenylmethane diisocyanate and polypropylene ether glycol. The same effect was obtained even when changed to). In addition, the isocyanate blend, which is a component of the binder polymer, was changed to Baytech WE-180 (180 g), Desmodur N3200 (available from Bayer, which is a biuret derivative of HDI) (120 g), and the polyol blend was changed to PMEG. The same effect was obtained even when the molecular weight was changed to 1000 (which is a polytetramethylene ether diol having a molecular weight of 1000) (300 g) and a molecular weight of 1500 polypropylene oxide triol (300 g).
Further, in Samples 201 to 204, the same effect was obtained even when the binder polymer was changed to a melamine formaldehyde resin, for example, poly (melamine-co-formaldehyde) methylated resin available from Aldrich Chemical Co.).

Example 3
[Hologram recording method using decoloring method (sensitizing dye + decolorizable dye)]
Hologram recording materials 301 to 307 were prepared in the same manner as in Example 1 except that the components shown in Table 5 were used. % Represents mass%.

The hologram recording material was exposed and recorded using a YAG laser double wave (532 nm, output 2 W) as a light source by the two-beam optical system for transmission hologram recording shown in FIG. The angle between the object beam and the reference beam is 30 degrees. The beam has a diameter of 0.6 cm and an intensity of 8 mW / cm ² , and the holographic exposure time varies from 0.1 to 400 seconds (irradiation energy ranges from 0.8 to 3200 mJ / cm ² ). And exposed. While exposing the hologram, a He—Ne laser beam of 632 nm was passed through the center of the exposure area at a black angle, and the ratio of the diffracted light to the transmitted light (relative diffraction efficiency) was measured in real time. In addition, since there is no absorption of a sensitizing dye at 632 nm, the He—Ne laser does not expose the hologram recording material.

  As a comparative example, a photopolymer hologram recording material of Example 1 (Comparative Example 2 below) of JP-T-2004-537620 was prepared.

  From Table 6, the examples described in the publicly known Japanese translations of PCT publication No. 2004-537620 are numerical values with insufficient M / #, sensitivity, and shrinkage although diffraction efficiency is high. . In contrast, the hologram recording materials 301 to 307 of the present invention are completely different from known hologram recording materials that perform hologram recording by refractive index modulation using a decoloring reaction without using mass transfer and polymerization. It can be seen that a high diffraction efficiency, an extremely small shrinkage ratio of 0.01% or less, and a high multiplicity M / # can be achieved, which is particularly suitable for holographic memory applications.

Furthermore, the hologram recording material of the present invention increases Δn (calculated based on Kugelnick's formula from refractive index modulation amount, diffraction efficiency and film thickness in interference fringes) almost linearly according to the exposure amount (mJ / cm ² ). However, this is advantageous for multiple recording.

  Actually, using the hologram recording material of the present invention, the multiplex hologram recording was performed 10 times in the same place by changing the angle of the reference light by 2 degrees with the light amount of 1/10 of the exposure amount giving the maximum diffraction efficiency. After that, it was confirmed that each object light can be reproduced by changing the angle of the reproduction light by 2 degrees and irradiating. That is, it can be seen that the hologram recording material of the present invention is capable of multiple recording with the same exposure amount and has multiple recording suitability. As described above, since the hologram recording material of the present invention can perform multiple multiplex recording, high-density (capacity) recording is possible.

  On the other hand, known photopolymer type hologram recording materials such as JP-T-2004-537620 perform the same recording in the latter stage of multiple recording because the polymerization of the photopolymer progresses and the movement of the monomer necessary for recording slows down. At this time, it was found that a larger amount of irradiation light was required than in the initial stage, which proved to be a problem in improving the multiplicity, that is, the recording density.

Example 4
[Remaining decolorizable dye latent image-hologram recording method by latent image sensitization polymerization method]
Hologram recording materials 401 to 404 were produced in the same manner as in Example 1 except that the components shown in Table 7 were used. % Represents mass%.

The hologram recording material was exposed and recorded using a YAG laser double wave (532 nm, output 2 W) as a light source by the two-beam optical system for transmission hologram recording shown in FIG. The angle between the object beam and the reference beam is 30 degrees. The beam has a diameter of 0.6 cm and an intensity of 8 mW / cm ² , and the holographic exposure time varies from 0.1 to 40 seconds (irradiation energy ranges from 0.8 to 320 mJ / cm ² ). (First step) A He—Ne laser beam of 632 nm was passed through the center of the exposure region at the black angle, and the ratio of the diffracted light to the transmitted light (relative diffraction efficiency) was measured in real time ( Diffraction efficiency after first step (η). In addition, since there is no absorption of a sensitizing dye at 632 nm, the He—Ne laser does not expose the hologram recording material.
Further, the entire surface was irradiated with light having a wavelength range of 370 to 410 nm (second step), and the diffraction efficiency was measured (diffraction efficiency η after the second step). Further, the amount of irradiation necessary to obtain the maximum diffraction efficiency only in the first step without using the second step is divided by the amount of irradiation necessary for the first step when the second step is used. Is the “amplification factor” and the above is summarized in Table 8.

  From Table 8, in the hologram recording material of the present invention, the amount of light applied to the first step can be reduced to 1/5 to 1/7 as compared with the case where the second step is not used. Since the second process is capable of batch exposure, the first process is shortened by amplification of refractive index modulation recording by causing polymerization using the remaining decolorizable dye in the first process as a latent image in the second process. That is, it can be seen that high sensitivity can be achieved. Needless to say, it is impossible to increase the sensitivity by such amplification with known materials as described in JP-T-2004-537620.

Furthermore, the hologram recording material of the present invention is substantially linear in accordance with the exposure amount (mJ / cm ² ) after the first step and after the second step, Δn (refractive index modulation amount, diffraction efficiency and film in interference fringes). This is advantageous in the case of multiple recording.

  Actually, using the hologram recording material of the present invention, 10 times of multiple hologram recording was performed at the same place by changing the angle of the reference light by 2 degrees with the light amount of 1/10 of the exposure amount in the first step. After performing (first step), the entire surface was irradiated with light having a wavelength range of 370 to 410 nm to perform recording amplification by polymerization (second step). The angle of the reproduction light was changed by 2 degrees and irradiated. By doing so, it was confirmed that each object light can be reproduced. That is, it can be seen that the hologram recording material of the present invention can perform multiple recording with the same exposure amount and has multiple recording suitability. That is, the holographic recording material of the present invention can perform many multiplex recordings and can perform high density (capacity) recording.

On the other hand, known photopolymer type hologram recording materials such as JP-T-2004-537620 perform the same recording in the latter stage of multiple recording because the polymerization of the photopolymer progresses and the movement of the monomer necessary for recording slows down. At this time, it was found that a larger amount of irradiation light was required than in the initial stage, which proved to be a problem in improving the multiplicity, that is, the recording density.
On the other hand, the hologram recording method of the present invention uses a decoloring reaction instead of polymerization for hologram recording (first step) and uses it as a latent image. Is excellent.

In Samples 301 to 307 and 401 to 404, sensitizing dyes are S-1, S-4, S-8, S-10, S-11, S-19, S-23, S-31, and S. -33, S-34, S-43, S-45, S-46, S-50, S-58, S-67, S-71, S-73, S-74, S-77, S-80 , S-81, S-88, S-91, S-94, S-95, S-96, the same effect was obtained.
Further, in samples 301 to 306, 401, and 402, decolorizer precursors (acid generators, sometimes combined acids or radical polymerization initiators) were changed to I-3, I-4, I-6, I-7, I. -8, I-9, I-10,4- (octylphenyl) phenyliodonium hexafluoroantimonate, tris (4-methylphenyl) sulfonium tetra (pentafluorophenyl) borate, triphenylsulfonium perfluoropentanoate, bis Even if it is changed to (1- (4-diphenylsulfonium) phenyl sulfide ditriflate, dimethylphenacylsulfonium perfluorobutanesulfonate, benzoin tosylate, I-22, I-23, samples 301 to 306, 401, 402 Acid decolorizable dyes are G-14, G-17, G-21, G-22, and G-26. Similar effects G-27 was obtained.
Further, in Samples 307 and 403, the decolorizer precursor (base generator, possibly also an anionic polymerization initiator) was changed to PB-3, PB-4, PB-5, PB-6, PB-7, PB-8. , PB-9, but the base decoloring dyes in Samples 307 and 403 are G-29, G-32, G-38, G-40, G-42, G-43, G-44, Even if it changed to G-45, the same effect was acquired. Further, even if the radical polymerization initiator is changed to I-1, I-11 to I-20 or the like in the sample 404, the decolorizable dyes in the sample 404 are G-48, G-49, G-51, Even if it changed to G-52, the same effect was acquired.
In Samples 301 to 303, 306, 307, and 402 to 404, the electron donors are A-2, A-3, A-4, A-5, A-6, A-9, A-10, A- The same effect was obtained even when changed to 11.
Further, in samples 301 to 307, the binder is changed to polymethyl methacrylate (Mw 996000, 350,000, 120,000), poly (methyl methacrylate-butyl methacrylate) copolymer (Mw 75000), polyvinyl acetate (Mw 83000), polycarbonate, cellulose acetate butyrate and the like. Even if it was changed, the same effect was obtained.
In Samples 301 to 307 and 401 to 404, Baytech WE-180, which is a component of the binder polymer, is Baytech MP-160 (available from Bayer, NCO terminal based on diphenylmethane diisocyanate and polypropylene ether glycol. The same effect was obtained even when the prepolymer was changed. In addition, the isocyanate blend, which is a component of the binder polymer, was changed to Baytech WE-180 (180 g), Desmodur N3200 (available from Bayer, which is a biuret derivative of HDI) (120 g), and the polyol blend was changed to PMEG. The same effect was obtained even when the molecular weight was changed to 1000 (which is a polytetramethylene ether diol having a molecular weight of 1000) (300 g) and a molecular weight of 1500 polypropylene oxide triol (300 g).
Further, in Samples 301 to 307 and 401 to 404, the same effect can be obtained even when the binder polymer is changed to a melamine formaldehyde resin (for example, poly (melamine-co-formaldehyde) methylated resin available from Aldrich Chemical). Obtained.
In the above case, the optimal wavelength was used for the light for performing the entire surface exposure in each system.

It is the schematic explaining the two-beam optical system for hologram exposure.

Explanation of symbols

10 YAG laser 12 Laser beam 14 Mirror 20 Beam splitter 22 Beam segment 24 Mirror 26 Spatial filter 28 Sample 30 Hologram recording material 32 He-Ne laser beam 34 He-Ne laser 36 Detector 38 Rotating stage 40 Beam expander

Claims (29)

  It has a photorefractive index modulating component and a curable polymer, and the photorefractive index modulating component includes 1) color development reaction, 2) latent image color development-colored body self-sensitized amplification color reaction, and 3) latent image color development-color development. Interference fringes are formed by any of the following methods: body-sensitized polymerization reaction, 4) orientation change of compound having intrinsic birefringence, 5) dye decolorization reaction, 6) residual decolorization dye latent image-latent image sensitization polymerization reaction. A hologram recording material, which is a component recorded as refractive index modulation.   The curable polymer forms a polymer matrix formed by a polymerization reaction, and the polymerization reaction includes a cationic epoxy polymerization reaction, a cationic vinyl ether polymerization reaction, a cationic alkenyl ether polymerization reaction, a cationic allyl ether polymerization reaction, a cationic ketene acetal polymerization reaction, Epoxyamine step polymerization reaction, epoxy mercaptan step polymerization reaction, unsaturated ester amine step polymerization reaction, unsaturated ester mercaptan step polymerization reaction, vinyl-silicon hydride step polymerization reaction, isocyanate-hydroxyl step polymerization reaction, isocyanate-amine step polymerization reaction The hologram recording material according to claim 1, wherein the hologram recording material is a polymerization reaction comprising a combination thereof.   The hologram recording material according to claim 1, wherein the curable polymer includes a reactive polymer and a crosslinking agent, and forms a polymer matrix by a polymerization reaction.   The hologram recording material according to claim 2, wherein the polymer matrix is formed by a thermal reaction.   The reaction for forming the polymer matrix is a reaction independent of the light refractive index modulation reaction of the light refractive index modulation component, and the light refractive index modulation component is not reacted during the polymer matrix formation reaction. The hologram recording material described in 1.   The hologram recording material according to claim 3, wherein the reactive polymer is a polyol, and the cross-linking agent is an NCO-terminated prepolymer.   The hologram recording material according to claim 6, wherein an exothermic peak occurs within 12 minutes after mixing the polyol and the NCO-terminated prepolymer.   The hologram recording material according to claim 6, wherein the polymerization reaction is a polymerization reaction comprising an isocyanate-hydroxyl step polymerization reaction, an isocyanate-amine step polymerization reaction, or a combination thereof.   The hologram recording material according to claim 6, wherein the NCO-terminated prepolymer is made of a material selected from aromatic isocyanate, aliphatic isocyanate, or a combination thereof.   7. The hologram recording material according to claim 6, wherein the NCO-terminated prepolymer comprises a substance selected from aromatic diisocyanate, hexamethylene diisocyanate, hexamethylene diisocyanate derivatives, or a combination thereof.   The hologram recording material according to claim 6, wherein the polyol is a polyol of polypropylene oxide.   The hologram recording material according to claim 6, wherein the polyol is made of polytetramethylene ether diol. The hologram recording material according to claim 6, wherein the hologram recording material has a thickness of 200 μm or more and Δn of 3 × 10 ⁻³ or more.   The NCO-terminated prepolymer comprises biscyclohexylmethane diisocyanate, an NCO-terminated prepolymer formed by reaction of biscyclohexylmethane diisocyanate with polytetramethylene glycol, butylated hydroxytoluene, and / or a derivative of hexamethylene diisocyanate. The polyol includes a polyol of polypropylene oxide and a polyol of polytetramethylene ether, and an exothermic peak occurs within 12 minutes after mixing the polyol and the prepolymer at the NCO end. 6. The hologram recording material according to 6.   The NCO-terminated prepolymer comprises a material selected from diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and a derivative of hexamethylene diisocyanate, and the polyol comprises a polyol of polypropylene oxide, and the polyol and the NCO The hologram recording material according to claim 6, wherein an exothermic peak occurs within 12 minutes after mixing with the terminal prepolymer.   The hologram recording material according to claim 1, wherein the curable polymer is made of a melamine-formaldehyde resin. A light-refractive index modulation component and a curable polymer, wherein the system of the light-refractive index modulation component and the curable polymer is phase-separated, and is approximately 7 × 10 ⁻³ in 90 ° light scattering at a wavelength effective for hologram formation. 2. The hologram recording material according to claim 1, wherein the hologram recording material has the following Rayleigh ratio and is formed by a reaction independent of a light refractive index modulation reaction of the light refractive index modulation component.   2) The method of recording a hologram by latent image color development-colored body self-sensitized amplification color development reaction includes at least a first step of generating a color body having no absorption at a hologram reproduction light wavelength as a latent image by hologram exposure; Unlike a hologram exposure, the interference fringes are recorded as a refractive index modulation by irradiating the color development latent image with light in the wavelength range where the molar absorption coefficient of the sensitizing dye is 5000 or less to generate self-sensitized amplification. The hologram recording material according to claim 1, comprising a second step and performing them by a dry process. As a group of compounds capable of holographic recording by the above 1) color development reaction or 2) latent image color development-chromogen self-sensitized amplification color development reaction, at least
1) a sensitizing dye that absorbs light by hologram exposure and generates an excited state; and 2) a dye that can be a color former that has a longer wavelength than the original state and has no absorption at the hologram reproduction light wavelength. An interference fringe recording component that contains a precursor and can record interference fringes using refractive index modulation by color development by electron transfer or energy transfer from a sensitizing dye or color former excited state;
The hologram recording material according to claim 1, comprising:   3) Latent image color development—A method for recording a hologram by color development sensitized polymerization reaction includes a first step of generating a color development body having no absorption at a hologram reproduction light wavelength as a latent image by hologram exposure; 2. The method according to claim 1, further comprising a second step of recording the interference fringes as refractive index modulation by irradiating the image with light having a wavelength different from that of the hologram exposure, and performing the dry process. The hologram recording material according to any one of 1 to 17. The compound group capable of holographic recording according to claim 20, at least,
1) a sensitizing dye that absorbs light and generates an excited state by hologram exposure in the first step;
2) Absorption becomes longer in wavelength from the original state by transferring electrons or energy from the excited state of the sensitizing dye in the first step or from the excited state of the chromophore in the second step. A group of dye precursors which can be a color former having an absorption in a wavelength region having a molar extinction coefficient of 5000 or less and having no absorption in a hologram reproduction light wavelength;
3) A polymerization initiator capable of initiating polymerization of the polymerizable compound by electron transfer or energy transfer from the sensitizing dye excited state in the first step and from the color former excited state in the second step,
4) a polymerizable compound, and 5) a binder,
The hologram recording material according to claim 1, comprising: 5) As a compound group capable of hologram recording by a dye decoloring reaction, at least
1) a sensitizing dye that absorbs light by hologram exposure to generate an excited state, and 2) a decolorizable dye or a radical generator, an acid generator, a base generator, and a nucleophile as an interference fringe recording component. Agent, electrophile generator, decolorizer precursor and decolorizable dye consisting of triplet oxygen,
After the sensitizing dye generates an excited state by hologram exposure, energy transfer to the decolorizable dye or electron transfer directly to erase the decolorable dye, or energy to the decolorizer precursor A decoloring agent is generated from the decoloring agent precursor by moving or electron transfer, and the decoloring agent decolors the decoloring dye, thereby forming an interference fringe by refractive index modulation. The hologram recording material according to claim 1.   6) A method for recording a hologram by a residual decolorizable dye latent image-latent image sensitizing polymerization reaction, wherein a sensitizing dye having absorption at a hologram exposure wavelength absorbs light during hologram exposure to generate an excited state. From the decolorizer precursor by decoloring the decolorizable dye by direct energy transfer or electron transfer to the decolorizable dye of Item 22, or by transferring energy or electron transfer with the decolorizer precursor A first step of generating a decoloring agent, and the decoloring agent decolorizes the decolorizable dye, thereby making the residual decolorable dye not decolored into a latent image, and the residual decolorizable dye A second step of recording the interference fringes as refractive index modulation by irradiating the latent image with light having a wavelength different from that of hologram exposure to activate the polymerization initiator by energy transfer or electron transfer to cause polymerization; thing The hologram recording material according to any one of claims 1 to 17, characterized. The compound group capable of holographic recording according to claim 23 is at least:
1) a sensitizing dye that absorbs light and generates an excited state by hologram exposure in the first step;
2) As a result of direct energy transfer or electron transfer from the sensitizing dye excited state in the first step, or as a result of generating a decolorant by transferring energy or electron to the decolorizer precursor, the color is erased. A decolorizable dye having a molar extinction coefficient of the hologram reproduction light wavelength of 1000 or less,
3) A decolorizer precursor of a polymerization initiator (possibly 2) capable of initiating polymerization of the polymerizable compound by electron transfer or energy transfer from the remaining decolorizable dye excited state in the second step. )
4) a polymerizable compound, and 5) a binder,
The hologram recording material according to claim 1, comprising:   The hologram recording material according to any one of claims 1 to 24, wherein the hologram recording is a system that cannot be rewritten.   The holographic recording material according to any one of claims 1 to 24, wherein multiple recording can be performed 10 times or more.   27. The hologram recording material according to claim 26, wherein the multiplex recording can be performed while the exposure amount at the time of multiplex recording remains constant throughout the multiplex recording.   An optical recording medium comprising the hologram recording material according to any one of claims 1 to 27.   An optical recording medium, wherein the hologram recording material according to any one of claims 1 to 27 is stored in a light-shielding cartridge at the time of storage.

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